PCAP’s Common Ground Series

This paper is one in a series of issue briefings the Presidential Climate Action Project is preparing for the presidential candidates and the next president’s transition team on issues where there is potential for bipartisan cooperation.

Executive Summary

Many of America’s top military and intelligence agencies during Republican and Democrat administrations have warned that climate change is a serious threat to national security.

National defense agencies call it a “threat multiplier” and an “accelerant of instability”, meaning that its impacts will make existing security threats more severe. Some nations in the most volatile regions of the world are likely to be further destabilized by the impacts of global warming. Some may suffer state failure. Others will experience humanitarian crises caused by weather disasters, famine, drought and floods. Millions of the world’s people will become climate refugees, displaced from their homelands by these climate impact.

In addition, climate change threatens the operations and effectiveness of U.S. military forces, most immediately from the impacts of rising seas on coastal military facilities and training grounds at home and abroad.i As the Center for Climate and Security explains:

Climate change has a direct impact on security through its effect on the critical infrastructure underpinning a nation’s security. This includes sea level rise risks to military installations that can degrade a nation’s ability to conduct military operations, as well as extreme weather events that can devastate essential energy, financial and agricultural centers that undergird a nation’s economic viability. By placing strains on the infrastructure and resources necessary for the viability of the nation-state system and the well-being of its populations, and by physically changing the geostrategic environment, climate change presents a risk to both national and international security.

Nevertheless, there are still elected officials who are skeptical that climate change is real or that it rises to the level of a national security concern. Whatever their opinions about climate science or the current manifestations of global warming, however, there can be no reasonable debate over the risk that the predictions of climate scientists and the conclusions of security experts are correct – that climate impacts will become more dangerous, disruptive, expensive and intolerable in the years ahead unless the United States and the rest of the international community take significant and immediate steps to manage these risks. 2

This paper briefly lists the conclusions of defense and intelligence officials and the climate mitigation and adaptation recommendations of knowledgeable military and civilian organizations. Its principal conclusion is that the security risks of global warming are very real and already present. The current threat multipliers are those who can help society confront climate change but who refuse to do so.


Based on credible science, observed realities and decades of experience assessing and protecting America’s interests, many of our top military and intelligence leaders have warned publicly that global climate change endangers national security and the military’s ability to perform its duties.

The threat is present in two ways. The first is indirect: Climate change is a “threat multiplier” that an “instability accelerant” that compounds existing challenges to world stability. Security analysts warn that climate impacts such as drought, rising sea levels and the growing number of environmental refugees can tip some of the most volatile and strategically important regions of the world into crisis, conflict and even state failures. As the U.S. Navy’s former oceanographer, Rear Admiral David W. Titley, warns, these are crises “the United States will almost certainly be called upon to deal with.” 3

The second threat is more direct: The impact of sea-level rise on the military’s coastal installations at home and abroad, for example, and the impact of extreme weather on military operations.

Timing is everything if we hope to prevent these problems and to adapt to those that already are inevitable. There is a real danger that critical environmental systems will reach tipping points where the impacts of global warming are irreversible. Researchers at the U.S. National Center for Atmospheric Research (NCAR), the Intergovernmental Panel on Climate Change (IPCC) and other institutions have concluded that several from global warming’s adverse affects will last for centuries and even thousands of years.4

Retired Four Star Generals Anthony Zinni (USMC) and Ronald Keys (USAF) and Admiral Frank Bowman (USN)v have put this in military terms:

“Today, as we pass another global heat record, we run the risk of being too late on climate change… Just as we have underestimated recent threats, such as the Islamic State and a revanchist Russia, we are in danger of underestimating those threats that follow a changing climate.”

Some of our highest-ranking retired military officers express dismay that discussions about these critical issues have become “polarizing and have receded from the arena of informed public discourse and debate.”vi Generals Zinni and Keys and Admiral Bowman are among them. “The bad news,” they have written, “is that while the military refuses to be ‘too late’ on climate change, short-sighted politics have prevented more robust action to reduce serious and costly risks.”

Yet there are positive signs that the politicization is waning. Some national security leaders in Congress, both Republican and Democrat, now agree publicly that global warming multiplies security threats.

What to do about it is a matter for legitimate debate. There should be no debate, however, about our leaders’ responsibility to protect the American people from significant security risks, especially those at so large a scale that they cannot be mitigated by businesses, citizens, cities and states alone. In fact, it is the risk management approach to climate action on which political leaders should be able to find common ground.

From the standpoint of risk management, it is not necessary to achieve unanimity on the causes and implications of climate change, or to wait until every detail is settled.vii We need only acknowledge the possibility that the majority of the world’s climate scientists are correct in their findings that global warming is real and impacts will become more and more costly in both human and economic terms if greenhouse gas emissions are not substantially curtailed.

In addition, the risk-management approach is one the American people can support. While most citizens are not well enough versed in the complexities of climate science to fully understand it, all of us are familiar with risk management. It is a routine part of our lives. From automobile, home and health insurance to seat belts and smoke alarms, we protect ourselves against events we hope will not occur but that we know could. Climate risk management would replace politics with prudence.

In short, the willingness of candidates for public office to acknowledge climate risks and take action to mitigate them should be a prerequisite for election. And because this is an issue that requires all hands to be on deck, the prerequisite should apply not only to candidates for the presidency and Congress, but also to candidates for state and local offices.

A Clear and Present Danger

Because science has determined that the pollution from fossil fuel combustion is the principal human cause of contemporary climate change, the first order of business is to transition away from those fuels. The energy that runs the economy of the United States and all other nations must be virtually carbon free. Ideally, our energy would also be renewable and ubiquitous to eliminate the danger that others will control our fuel supplies and prices, our energy resources will be depleted, or their social and environmental costs will outweigh their benefits.

There was a time in the last century when mitigating climate change and making the transition to clean energy would have been significantly less difficult and expensive than it is today. We should learn from this: Action now is much less disruptive and expensive than it will be in the future. As an expert panel convened by the National Academy of Sciences notes, “emission reduction choices made today matter in determining impacts that will be experienced not just over the next few decades, but also into the coming centuries and millennia.” 8

Today’s choices affect the security of our energy supplies; the stability of our economy; the health and welfare of our communities; the future of our children; the cost of government; the demands placed on U.S. military forces; the condition of the environment; the availability of vital resources such as water; and much more.

Our top military and intelligence officials have warned for more than a decade that global climate change is a serious threat on all of these fronts.ix The threats are no longer just informed speculation; they are a clear and present danger. The national Global Change Research Programx (GCRP) concluded in 2014:

Climate change, once considered an issue for a distant future, has moved firmly into the present …The observed warming and other climactic changes are triggering wide-ranging impacts in every region of our country and throughout our economy. 11

Government Risk Assessments

Public records show that the U.S. government has been aware of climate change for more than 50 years. President Lyndon Johnson’s science advisors gave him a prescient briefing in 1965, telling him that the combustion of fossil fuels was elevating carbon dioxide concentrations in the atmosphere. “This will modify the heat balance of the atmosphere to such an extent that marked changes in climate, not controllable through local or even national efforts, could occur,” President Johnson’s Science Advisory Committee predicted. Johnson conveyed this information to Congress in a special message that year, the first time a president warned the American people about climate change.xii

Since then, Congress has created nearly 100 statutory provisions that explicitly address climate change, global warming, or greenhouse gas emissions.xiii Many of these laws and resolutions include definitive statements by Congress that climate change “pose(s) serious threats to human health and the environment on a global scale”. In other words, past congresses accepted the basic findings of the science community long ago.

In 1990, two years after the United Nations and the World Meteorological Organization launched the largest scientific undertaking in history – the Intergovernmental Panel on Climate Change (IPCC) — Congress created a parallel effort, the Global Change Research Program, to assess climate impacts in the United States. Today, the Program coordinates the research of 13 federal agencies and issues reports to Congress and the President every four years.

As climate scientists issued increasingly confident conclusions about climate disruption, political debate intensified over its causes and consequences. Nevertheless, both the Republican nominee for the presidency and the Republican Party’s Platform in 2008 acknowledged the need to do something about global warming. The GOP Platform mentioned climate change nine times, including the statement that “the United States should take measured and reasonable steps today to reduce any impact (of carbon emissions) on the environment. Those steps, if consistent with our global competitiveness, will also be good for our national security, our energy independence, and our economy.” Four years later, the GOP Platform avoided any mention of global warming except to criticize President Obama for overreacting.

The closest that recent congresses have come to an effective policy response was in 2009. With early warnings from defense and intelligence officials that global warming would be a direct threat to the national interest, the House of Representatives approved a bill to establish a national carbon-trading regime. The bill died, however, when the Senate failed to take it up.xiv Since then, most legislative action has focused unsuccessfully on limiting the federal response to climate change including the Environmental Protection Agency’s (EPA) authority to regulate greenhouse gas emissions.xv

With the increasingly worrisome conclusions of climate science on their radar, U.S. defense, intelligence and homeland security agencies have conducted their own assessments of global warming. For example:

The National Intelligence Council 17 concluded in 2008, “From a national security perspective, climate change has the potential to affect lives (for example, through food and water shortages, increased health problems including the spread of disease, and increased potential for conflict), property (for example through ground subsidence, flooding, coastal erosion, and extreme weather events), and other security interests. The United States depends on a smooth-functioning international system ensuring the flow of trade and market access to critical raw materials such as oil and gas, and security for its allies and partners. Climate change and climate change policies could affect all of these—domestic stability in a number of key states, the opening of new sea lanes and access to raw materials, and the global economy more broadly—with significant geopolitical consequences.”

The Department of Homeland Security18 reported in 2013 that, “As the impacts of climate change place increasing stress on global and national economic security and safety systems, this issue will continue to absorb the attention of the Nation’s leaders. Meanwhile, America is increasingly responding to natural events, requiring large amounts of capital for response and recovery efforts at the local, regional, and Federal levels. Future, simultaneous shocks to both global and national economic systems could trigger the perfect storm with negative consequences.”

Also in 2013, the National Research Council18 warned, “A key characteristic of these (climate) changes is that they can come faster than expected, planned, or budgeted for, forcing more reactive rather than proactive modes of behavior”.

The Department of Defense (DoD) 2014 Quadrennial Defense Review19 concluded, “The pressures caused by climate change will influence resource competition while placing additional burdens on economies, societies, and governance institutions around the world. These effects are threat multipliers that will aggravate stressors abroad such as poverty, environmental degradation, political instability, and social tensions – conditions that can enable terrorist activity and other forms of violence.”

DoD’s 2014 Climate Change Adaptation Roadmap20 explained, “In our defense strategy, we refer to climate change as a ‘threat multiplier’ because it has the potential to exacerbate many of the challenges we are dealing with today – from infectious disease to terrorism. We are already beginning to see some of these impacts.”

The White House National Security Strategy24 concluded in 2015, “Climate change is an urgent and growing threat to our national security, contributing to increased natural disasters, refugee flows, and conflicts over basic resources like food and water. The present day effects of climate change are being felt from the Arctic to the Midwest. Increased sea levels and storm surges threaten coastal regions, infrastructure, and property. In turn, the global economy suffers, compounding the growing costs of preparing and restoring infrastructure.”

Also in 2015, a DoD Report to Congress22 advised, “The Department of Defense sees climate change as a present security threat, not strictly a long-term risk. We are already observing the impacts of climate change in shocks and stressors to vulnerable nations and communities, including in the United States, and in the Arctic, Middle East, Africa, Asia, and South America … Although climate-related stress will disproportionately affect fragile and conflict-affected states, even resilient, well-developed countries are subject to the effects of climate change in significant and consequential ways.” In addition, the report emphasizes the vulnerability of defense installations and assets to climate impacts.xxiii

In 2016, the Director of National Intelligence24, James Clapper, noted “Unpredictable instability has become the ‘new normal’, and this trend will continue for the foreseeable future…Extreme weather, climate change, environmental degradation, rising demand for food and water, poor policy decisions and inadequate infrastructure will magnify this instability.”

DoD Directive 4715.2125, issued in 2016 by Deputy Secretary of Defense Robert O. Work, has been called one of the potentially most significant directives in recent Pentagon history. It orders “every corner of the Pentagon, including the office of the secretary of defense, the joint chiefs of staff, and all the combatant commands around the world, to put climate change front and center in their strategic planning.”xxvi

In May 2015, the White House issued a compilation of all these documents and concurred with their conclusions. In September 2016, President Obama directed that all federal agencies “ensure that climate change-related impacts are fully considered in the development of national security doctrine, policies and plans.”xxvii

Outside the Chain of Command

Some critics have dismissed the warnings from military officers, saying that they are obligated to echo the positions of the Commander in Chief. However, military leaders have done a number of things to address climate change without orders from the White House, and the conclusions that climate change compounds security threats have spanned Republican and Democrat administrations. More important, perhaps, urgent warnings have come from senior retired officers who served in high command positions in all four branches of the military but are now outside the chain of command. They have been candid. Based on their own research and their knowledge of military and intelligence threats, they have issued their own warnings that climate change is a “threat multiplier”.

Many of these former senior officers participate in national organizations that study the climate/security nexus (Attachment 1). The organizations include the Center for Climate and Security, a nonpartisan security and foreign policy institute that conducts research on the security/climate interface and is advised by a board of senior retired military and national security leaders; the CNA Military Advisory Board (MAB), which has studied the security dimensions of climate change and fossil energy use since 2007xxviii; and the American Security Project, a nonpartisan group whose members include retired military flag officers, former members of Congress, business leaders and former government officials.

The retired generals and admirals on the MAB have concluded, “During our decades of experience in the U.S. military, we have addressed many national security challenges, from containment and deterrence of the Soviet nuclear threat during the Cold War to political extremism and transnational terrorism in recent years. The national security risks of projected climate change are as serious as any challenges we have faced.” xxix

Participants in the American Security Project advise, “Climate change is a are taking seriously. Climate change alone will not cause wars, but it serves as an ‘accelerant of instability’ or a ‘Threat Multiplier’ that makes already existing threats worse… We must address the threats of climate change – both by reducing emissions and by increasing resiliency. Failure to do so will make solving every other security challenge of the 21st century nearly impossible.”

The Center for Climate & Security, which also has an Advisory Board of retired flag officers and national security experts, says, “Climate change, in both scale and potential impact, is a strategically-significant security risk that will affect our most basic resources, from food to water to energy… (P)rogress in comprehensively preventing, preparing for, adapting to and mitigating these risks will require that policy-makers, thought leaders and publics take them seriously.”

Civil Defense

According to the Intergovernmental Panel on Climate Change (IPCC), developed nations liked the United States need to cut their greenhouse gas emissions 25-40% below 1990 levels by 2020, just four years from now.xxx But in 2013, U.S. emissions began rising again after dropping during the 2008-2012 recession; they rose again in 2014 by 1%, reaching a level higher than in 1990.

The national policies necessary to drive down emission reductions more quickly include market-based measures such as carbon pricing and energy subsidy reforms. Both have been nonstarters in recent congresses, where climate-action opponents have blocked progress. As a result, the Environmental Protection Agency is taking steps to regulate greenhouse gas emissions from power plants, a major source. At this writing, nearly 30 states have sued the Administration in an effort to roll back the regulation, further delaying the process of national carbon-cutting.

In the war against global warming, unlike other wars, it is not just our men and women in uniform who will pay the price of inaction. We all will suffer the consequences. Nevertheless, political polarization about climate change or even managing its risks is evident in the 2016 presidential election campaign, where the leading candidates for the Republican Party’s nomination and the eventual nominee, Donald Trump, have dismissed climate science. Yet the security threats of global warming extend to virtually every community and household in the United States, as we are seeing regularly with the record weather disasters and warming confronting the American people today.

The key to change is the nation’s voters and it appears that weather disasters are persuading more of us that climate change is affecting homeland security. Researchers at the Yale Project on Climate Change Communicationxxxi report that 73% of American voters now agree that climate change is underway, up 7 points from two years ago. Among liberal and moderate Republicans, 71% agree that climate change is happening, up 10 points. And while only 47% of conservative Republicans acknowledge that climate change is underway, that response is up 19 percentage points, the largest shift of any group.

The question is when opinions will become votes. In the same survey, voters ranked climate change 19th in importance among 23 issues that Yale asked them about. That response is typical of most ranking polls today. It sends a signal to elected officials that the support of campaign donors is more important to remaining in office than paying attention to opinion polls.

In the final analysis, the civic duty to vote is the best civil defense against the worst impacts of global warming.


Figure 1. US greenhouse gas emissions since 1990. (Credit: EPA annual Inventory of U.S. Greenhouse Gas Emissions and Sinks 1990-2014)

Recommendations from Civil Society

Non-government organizations, academia and private sector have offered numerous suggestions for changes in public policy. The Council on Foreign Relations issued an agenda for action in 2007xxxii, including these recommendations:

  • The United States should prioritize so-called no-regrets policies, those that it would not regret having pursued even if the consequences of climate change prove less severe than feared.
  • The importance of climate policy to national security demands that it receive much greater prioritization across the U.S. federal government… Given the strong links between climate change and security, the rebuilding of a cadre of officials focused on climate should begin at the Pentagon.
  • All of the U.S. government’s tools should be mobilized against climate change. This requires high-level attention by White House officials who lead the interagency process.

The Center for American Progress’s recommendations include:33

  • Conduct federal government institutional reform in the United States that addresses the development-security relationship and that prioritizes planning for long-term humanitarian consequences of climate change and migration as a core national security issue.
  • Develop strategies to strengthen intergovernmental cooperation on trans-boundary risks in different regions of the world.
  • Ensure better information flows and more effective disaster response for early warning systems.
  • Support the best science to expand our understanding of specific circumstances such as desertification, rainfall variability, disaster occurrence, and coastal erosion, and their relation to human migration and conflict.
  • Identify regions most vulnerable to climate-induced migration, both forced and voluntary, in order to target aid, information, and contingency-planning capabilities.
  • View migration as a proactive adaptation strategy for local populations under pressure due to increased environmental change.

The Center for Climate and Security advises:

  • Risks to national and international security posed by climate change should be treated with urgency similar to other significant security threats. They have been underestimated.
  • National security planners and other key actors across the U.S. Government should constantly update and share information on climate change risks and integrate the information into planning to ensure that the U.S. is adequately prepared for this changing security landscape.


Members of the American Security Project say “We live in a time when the threats to our security are as complex and diverse as terrorism, nuclear proliferation, climate change, energy challenges, and our economic wellbeing. Partisan bickering and age- old solutions simply won’t solve our problems. America – and the world – needs an honest dialogue about security that is as robust as it is realistic.”

The Partnership for a Secure America (PSA) says “We believe that the United States is being ill-served by the growing partisan divide surrounding its national security and foreign policy. Although partisan rancor has traditionally stopped ‘at the water’s edge,’ this tradition of bipartisan cooperation has eroded significantly in recent years in negative and harmful ways. Policy differences must always be debated, but growing partisan bitterness dangerously interferes with substantive discussion of our national security and foreign policy.”

Similar reactions are occurring at the international level. Achim Steiner, the executive director of the U.N. Environment Programme, notes, “The question we must continuously ask ourselves in the face of scientific complexity and uncertainty, but also growing evidence of climate change, is at what point precaution, common sense or prudent risk management demands action.”

One of the key issues in 2016 – arguably the key issue – is whether the American people will insist that candidates for public office acknowledge the significant risks posed by climate change and describe in detail what they will do to about them.

Climate change has been politicized but it is not an inherently political issue. As former Colorado Gov. Bill Ritter has said, our understanding of climate change is a scientific issue; the need to act is a moral issue; and how to act is a governance issue.

As it turns out, what is good for national security in regard to global warming also is good for the economy, for jobs, for keeping government spending from spinning out of control, for keeping America internationally competitive in the rapidly growing clean energy sector, and for cleaner air and better health for the children who breath it. It is time for politicians to meet on common ground and to change the energy policies at the root of carbon dioxide pollution and climate change.

The Presidential Climate Action Project is a nonpartisan initiative to identify public policies that address global climate change and America’s transition to clean energy in ways that are consistent with progressive and conservative values. PCAP is advised by a national committee that includes several of the nation’s most distinguished thought leaders from both political parties. For more information about PCAP and to obtain other reports in this series, visit www.pcap2016.org or contact Executive Director William Becker at beckerncs@gmail.com.

Updated: Oct. 1, 2016

Attachment 1
Experts Have Spoken

America’s premier experts on risk are the members of the defense and intelligence communities. It is their job to anticipate and prepare for threats well in advance of their materialization. The following are among the many current and former military leaders who have added their voices to the warnings that climate change is an urgent national and international security issue.xxxiv

CNA’s Military Advisory Board

General Paul Kern, USA (Ret.) Former Commanding General, Army Materiel Command
Vice Admiral Lee Gunn, USN (Ret.) Former Inspector General of the Department of the Navy
Admiral Frank “Skip” Bowman, USN (Ret.) Former Director of the Naval Nuclear Propulsion Program and Former Chief of Naval Personnel
General James Conway, USMC (Ret.) Former Commandant of the Marine Corps
Lieutenant General Ken Eickmann, USAF (Ret.) Former Commander, U.S. Air Force Aeronautical Systems Center
Lieutenant General Larry Farrell, USAF (Ret.) Former Deputy Chief of Staff for Plans and Programs, Headquarters, U.S. Air Force
Brigadier General Gerald E. Galloway, Jr. USA (Ret.), former Dean at the United States Military Academy, West Point; Dean at the Industrial College of the Armed Forces, National Defense University
General Don Hoffman USAF (Ret.) Former Commander, U.S. Air Force Materiel Command
General Ron Keys, USAF (Ret.) Former Commander, U.S. Air Force Air Combat Command
Rear Admiral Neil Morisetti, British Royal Navy (Ret.) Former UK Foreign Secretary’s Special Representative for Climate Change and Former Commandant, UK Joint Services Command and Staff College
Vice Admiral Ann Rondeau, USN (Ret.) Former President, National Defense University and Former Deputy Commander, U.S. Transportation Command
Lieutenant General Keith Stalder, USMC (Ret.) Former Commanding General, U.S. Marine Corps Forces, Pacific
General Gordon Sullivan, USA (Ret.) Former Chief of Staff, U.S. Army
Rear Admiral David W. Titley, USN (Ret.) Former Oceanographer of the Navy
General Charles “Chuck” Wald, USAF (Ret.) Former Deputy Commander, U.S. European Command
Lieutenant General Richard Zilmer, USMC (Ret.) Former Commandant for Manpower and Reserve Affairs, and Former Commanding General of Multi-National Force – West in Al Anbar Province, Iraq

The Center for Climate and Security

Brigadier General John Adams, U.S. Army (Ret)
Brigadier General Joseph R. “Bob” Barnes, U.S. Army (Ret)
Lieutenant Commander Oliver-Leighton Barrett, U.S. Navy (Ret)
Admiral Frank L. “Skip” Bowman, U.S. Navy Rret)
Lieutenant General John G. Castellaw, U.S. Marine Corps (Ret)
Brigadier General Stephen A. Cheney, U.S. Marine Corps (Ret)
Brigadier General Gerald Galloway Jr., USA (Ret)
Captain Leo Goff, U.S. Navy (Ret)
Lieutenant General Arlen D. Jameson, USAF (Ret)
General Ronald E. Keys, U.S. Air Force (Ret)
Admiral Sam J. Locklear, USN (Ret)
Colonel Mark “Puck” Mykleby, USMC (Ret.)
Commander David Slayton, USN (Ret)
Rear Admiral David W. Titley, U.S. Navy (Ret)
Rear Admiral Jonathan White, USN (Ret)
General Anthony C. Zinni, U.S. Marine Corps (Ret)

The American Security Project

Lieutenant General John Castellaw, USMC (Ret)
Lieutenant General Daniel Christman, USA (Ret)
Admiral William Fallon, USN (Ret)
Vice Admiral Lee Gunn, USN (Ret)
Lieutenant General Claudia Kennedy, USA (Ret)
General Lester L. Lyles, USAF (Ret)
Lieutenant General Norman Seip, USAF (Ret)

Partnership for a Secure America

Madeleine Albright, former Secretary of State
William Cohen, former Secretary of Defense
Paula Dobriansky, Undersecretary of State under George W. Bush
Slade Gordon, R-WA, US Senate (ret)
Lee Hamilton, D-IN, US Rep. (ret)
Gary Hart, D-CO, US Senate (ret)
Carla Hills, former US Trade Representative
Nancy Kassebaum Baker, R-KS, US Senate (ret)
Thomas Kern, former Governorof New Jersey
John Lehman, Secretary of the Navy under Ronald Reagan
Richard Lugar, R-IN, US Senate (ret)
Donald McHenry, former Ambassador to the United Nations under Jimmy Carter
Robert McFarlane, National Security Advisor under Ronald Reagan
Sam Nunn, D-GA, US Senate (ret)
Leon Panetta, Secretary of Defense and Director of the CIA under Barack Obama
William J. Perry, Secretary of Defense under Bill Clinton
Thomas Pickering, Undersecretary of State and Ambassador under several presidents
George P. Shultz, Secretary of State under Ronald Reagan and Richard Nixon
Frank Wisner, Undersecretary of Defense under Bill Clinton, Undersecretary of State under George H.W. Bush, U.S. Ambassador under Ronald Reagan and Jimmy Carter