Republicans and Democrats already are laying the groundwork for the mid-term elections coming up in November, foretelling another summer of campaign ads and debates. Voting without the presidency on the ballot usually does not inspire a lot of excitement. The voter turnout four years ago was the worst in 72 years

But this election should be different at the state as well as national levels. If it becomes a referendum on Donald Trump, we will see whether it impacts Republican control of most governorships and state legislatures.

That is just one of several important issues that will not be printed on the November ballots, but will be between the lines.

Another is whether Republicans or Democrats will control the congressional redistricting after the 2020 census. In most states, the legislators chosen in November will be in charge of redistricting and the governors will have veto power. Election experts will be watching for the not-uncommon practice of gerrymandering, where the party in power draws congressional districts for its political advantage. Earlier this month, a federal court declared that congressional districts drawn by North Carolina were unconstitutional because they were gerrymandered.

Another question will be whether voter participation overcomes voter suppression, like we saw when Alabamans elected Doug Jones to the U.S. Senate last month. Alabama is one of two dozen states that have enacted laws and procedures designed to keep minorities from voting. But Black voters turned out in sufficient numbers to overcome the barriers to elect a Democrat in one of the nation’s reddest states.

Since 2010, nearly half the states have enacted laws that make it harder for poor and minority citizens, according to the Brennan Center for Justice. Voting rights groups will be watching to see whether get-out-the-minority-vote efforts will overcome these barriers in other states this fall. History will be made if minority and poor citizens cast enough ballots to show that voter suppression no longer works.

There is another group hoping that the fall election will be a bellwether event: the people who understand that global climate change is one of the most important issues in the country today and that it is becoming more important virtually every day that we do not do something about it.

This constituency, in which I am a member, has hoped for decades that federal, state and local elections would put people in office who would fight for clean energy, climate-change adaptation, and programs to encourage natural carbon storage in healthy soils, forests and grasslands. That finally happened with the election of Barack Obama, but all of his climate work is being undone Donald Trump. The current Congress is letting is happen.

This election should favor candidates, whether Republican or Democrat, who understand the urgency of climate action and who have specific commitments on what they’ll do in office. It should also reelect the growing number of Republican incumbents in Congress who are openly acknowledging the need for climate action, but who are constrained by more conservative members of the Party.

This year, a nonpartisan climate-action vote is not unrealistic. Research released last month shows that monolithic Republican resistance to climate action has started breaking down. The study analyzed Republican opinions at the level of congressional districts and found that “Pockets of Republicans, or even a plurality or majority, support some pro-climate positions” such as regulating carbon dioxide as a pollutant and investing more in renewable energy research.

As we might expect, those pockets are most noticeable in districts that already are experiencing adverse climate impacts – for example, along the coasts where extreme storms and rising sea levels are happening. The study showed that in the average congressional district, 50% of Republicans acknowledge that climate change is happening although only 31% think that humans are causing it.

There can be no denying that the United States is being hit with unprecedented weather disasters. There were 16 mega-disasters last year (disasters that caused more than $1 billion in damages). They tied the all-time record set in 2011. They caused more than $300 billion in damages, also a record. They killed 362 Americans.

The annual average of billion-dollar weather disasters was 5.8 events between 1980 and 2017. That average has doubled to 11.6 events in the last four years. Many weather events were downright weird, another sign of a changing climate. Cases in point included the cold front that hit the Deep South last July and the warm spell that broke records a year ago in Vermont.

In short, insofar as the fall election becomes a referendum on Donald Trump, it should reflect that his denial of climate change puts millions of Americans including Republicans at much greater risk of deaths, damages and health problems made worse by climate change. At the state level, the mid-term outcome will influence whether states and cities will fulfill their promises to achieve U.S. goals for reducing carbon pollution under the Paris climate accord.

Finally, if the mid-term election gives Democrats control of either the Senate or the House, we may see Congress resume its responsibility to check and balance the president’s powers. As CNN political analyst Ronald Brownstein has written, “As the 2018 election year begins, one question above all is likely to shape its outcome: Will Americans vote to constrain President Donald Trump by electing a Democrat-led Congress that will challenge and resist him, or to empower the Republicans who are increasingly working in harness with him?”

Stay tuned and involved.