Some of the most consequential elections for climate policy this fall could be the 36 governor’s races, where a blue wave could position clean energy advocates as a significant counterforce against the Trump administration’s fossil fuel agenda.

Republicans currently hold a near-record 33 governorships—a lock on power that has served as a brake on clean energy progress in some areas.

But the tide may be ready to turn. As many as a third of those seats are considered toss-ups or are leaning Democratic in the upcoming election, according to analysts like the Cook Political Report and University of Virginia political scientist Larry Sabato.

Several of the Democratic contenders have 100 percent clean energy commitments in their platforms, and many others support ambitious renewable portfolio standards, net-metering incentives and other climate policies.

The model for environmental advocates is New Jersey Gov. Phil Murphy, a Democrat elected last November who has reversed several of the policies of his Republican predecessor, Chris Christie. He reinstated New Jersey’s membership in the Northeast’s carbon cap-and-trade system known as the Regional Greenhouse Gas Initiative, and signed legislation to mandate that utilities obtain 50 percent of their electricity from renewable sources by 2030. With Murphy’s first appointee, the state’s Public Utility Commission now has a Democratic majority and a mandate to come up with a new program to incentivize rooftop solar.

“The most critical policies are set at the state level,” said Adam Browning, executive director of Vote Solar. “When it comes to the renewable energy agenda, the future is very much on the ballot this November.”

These are some of the ways state policies could change:

• In Nevada, New Hampshire, New Mexico and Maine, the state legislatures passed renewable energy initiatives in the past year and a half that had bipartisan support—but were vetoed by GOP governors.
   
• In 38 states, governors have the power to appoint members of public utility commissions—the regulatory bodies that make decisions affecting billions of dollars of energy infrastructure investment.
   
• Many of the governors elected this fall will have a key role in the reshaping of Congressional districts after the 2020 census.  

Advocates and opponents of climate policies and clean energy have been pouring millions of dollars into the races.

“For the first time in a decade, we could have enough state legislatures to take proactive action on climate change and renewable energy,” said Leslie Martes, state electoral campaigns director for the League of Conservation Voters, which is spending a record $25 million on state races this year—more than doubling its previous high mark set in 2016.

Freedom Partners Action Fund, one of the political vehicles of the petrochemical billionaire Koch brothers, is blasting the airwaves in Nevada to support GOP candidate Adam Laxalt and has deployed aggressive digital targeting techniques to bolster Republican Ron DeSantis in Florida.

Here are a few of the close gubernatorial races to watch for the future of clean energy policies:

Colorado

The Colorado race provides some of the country’s starkest contrasts on energy and the environment. Democratic nominee Jared Polis says he wants the state to commit to 100 percent clean energy by 2040—which would be the most ambitious timetable of any state. Republican nominee Walker Stapleton, his opponent, argues that  energy regulation carries high costs.

They are vying to succeed John Hickenlooper, a Democrat and former Denver mayor, in a state that lately has leaned slightly toward Democrats but remains winnable for Republicans. Colorado, which a history of mining and oil production, today has a rapidly growing clean-energy economy and a robust coalition of environmental advocates, and environmental issues are often prominent there.

“For our climate, for our national security, for our health, and for our economic growth, we need a bold goal of 100 percent renewable energy,” Polis, a member of Congress whose district includes Boulder, said on his campaign website.

Stapleton, Colorado’s state treasurer and a second-cousin of George W. Bush, says he wants to develop oil and gas resources in a responsible way and says Polis’ approach is bad for the economy.

Michigan

Michigan’s Democratic candidate for governor is Gretchen Whitmer, a former state legislator and outspoken critic of the way the state handled the lead poisoning crisis in Flint’s water system. Whitmer, who also has embraced a goal of 100 percent renewable energy, has made clean water issues a key part of her platform.

Oil pipelines are another election issue in Michigan. Whitmer says that if elected, she would announce an immediate plan to shut down Enbridge’s 65-year-old Line 5, which carries Canadian oil beneath the environmentally sensitive Straits of Mackinac.

Her Republican opponent, Bill Schuette, the state’s attorney general, has portrayed himself as a moderate on energy issues, much as current GOP Gov. Rick Snyder has done. Schuette stands out among Republican gubernatorial candidates this cycle for touting a record of protecting the environment. He brought charges against officials involved in the Flint crisis and co-chaired a task force that called for steps to reduce risks on Line 5, including a ban that was implemented on transporting heavy crude.

Line 5’s “days are numbered,” Schuette has said repeatedly. But the Michigan League of Conservation Voters is backing Whitmer, and running digital ads criticizing Schuette for not using the authority he has as the state’s top legal officer to shut down the pipeline.

New Mexico

The fracking boom is on track to deliver an unprecedented $1.2 billion windfall and a difficult decision on the energy future to the next governor of New Mexico. Try to keep the gravy train running, or curb the state’s fossil fuel dependency? As recently as 2016 and 2017, New Mexico legislators were grappling with budget shortfalls due to the boom-bust cycle in the oil business. The state also faces rates of poverty and unemployment that are among the nation’s highest.

U.S. Rep. Michelle Lujan Grisham, the Democratic contender, has said the revenue surge “dramatically highlights the need for leadership” for a “renewable energy economy” and has pledged to work for 50 percent renewable production in the state by 2030. Grisham, who had an LCV voting record of 100 percent last year, wants to reverse the policies of term-limited GOP Gov. Susana Martinez, who since 2015 has vetoed three solar incentive bills passed by the Democratic-controlled state legislature.

Recent polls show Grisham with a solid lead over Republican U.S. Rep Steve Pearce, who owned and operated an oilfield services company before he was elected to Congress 14 years ago. Pearce admits the state needs to diversify its revenue sources, but he has blasted Grisham for what he said is “a plan to shut down this oil boom and dry up critical funding for our state.” The oil and gas industry far and away has been Pearce’s top political career benefactor.

Nevada

In his bid for governor, Democrat Steve Sisolak touts his record in helping to make Clark County, home to Las Vegas, a leader in solar energy. In one ad, Sisolak dons sunglasses and strolls through one of the eight solar fields that was developed there during his tenure as county commission chairman. “Donald Trump wants to pull the plug on renewables,” he said. “As governor, I want Nevada to lead the nation on clean energy.”

Rooftop solar in Nevada only recently regained its footing after the Democratic-controlled state legislature reinstated net-metering, which had been curtailed in 2015 by the state’s Public Utilities Commission. GOP Gov. Brian Sandoval signed the measure reinstating the popular program, but he vetoed legislation that would have established a commuity solar program and boosted the state’s renewable energy standard—its requirement that utilities acquire a minimum amount of electricity from clean sources. In November, voters will have a chance to vote on a ballot initiative that would raise the standard to 50 percent by 2030—a measure Sisolak has said he supports.

Recent polls show Sisolak opening up a lead over Republican candidate Adam Laxalt, the state’s attorney general, who appears to take a swipe at the renewable energy standard proposal in the issues section of his website. “Too often, the heavy hand of government is used to try to force particular energy solutions on the entire population,” he said. “I will also oppose efforts to impose or expand costly and burdensome mandates on energy providers, which only lead to higher prices that hurt Nevada’s families, and have a particularly damaging impact on those with lower incomes.”

Laxalt was one of a cadre of Republican attorneys general who sued the Obama administration repeatedly over its environmental policies. Although Nevada stayed officially neutral in the legal battle over the Clean Power Plan—the Obama administration signature climate initiative—Laxalt filed a brief challenging the legality of using the Clean Air Act to cut carbon emissions from power plants. He also filed briefs opposing state investigations by New York and Massachusetts into whether ExxonMobil misled investors on climate change.

The Koch brothers’ Freedom Partners Action Fund is spending at least $1.5 million in TV ads to bolster Laxalt for his “record of getting the job done by saving taxpayers money as the state’s attorney general,” while bashing Sisolak for what it called “crony politics.” The Nevada Conservation League, an affiliate of LCV, has launched a $1.15 million ad campaign slamming Laxalt for his ties to the Koch brothers and Big Oil.

Maine

Wind energy developers are eager to see if this year’s gubernatorial election will mean a positive policy shift for renewables. GOP Gov. Paul LePage, who views wind power as a “boutique” energy source, has fought development as too costly and potentially damaging to tourism. He imposed a moratorium on new wind turbine permits in January, just as neighboring Massachusetts was rolling out its plan to boost renewables. LePage set up a commission ostensibly to study the issue, but in September one of its most outspoken members—a wind energy foe—resigned, saying it had not held a single meeting.

The Democrat running to take LePage’s place is Maine’s attorney general, Janet Mills, who has clashed with the governor repeatedly, including over his wind moratorium. If elected governor, she has said, she would allow it to expire.

“Maine has the resources and the expertise to lead the entire nation in growing the clean energy economy, creating good-paying jobs, cutting pollution and lowering energy costs,” Mills has said. “What we’ve been missing is a leader willing and ready to take advantage of those opportunities.”

Her opponent, Republican Shawn Moody, an auto body entrepreneur who is making his first run for public office, has recruited LePage’s daughter, chief strategist and other staffers to work on his campaign and has vowed to carry on LePage’s legacy—making clear he has similar views on renewables. “In the long term, renewable energy can play an important role in this energy strategy, but we cannot subsidize high-priced sources of energy, or special interests, at the expense of Maine people,” he has said. Moody believes every project should be reviewed to ensure that the state’s energy focuses on reducing costs, adding, “we must not permanently damage Maine’s landscape.”

When asked in a televised debate this summer if he believed humans contributed to the change in Maine’s environment through climate change, Moody said, “It’s mostly,” then paused before saying “no.”

Wisconsin

Wisconsin Gov. Scott Walker, a national Republican figure in large part because of his anti-union stances, is running for a third term and faces what may be his most formidable challenger in Tony Evers, a Democrat who is state superintendent of schools.

Walker is notorious for his anti-regulatory agenda and for his dependence on the Koch brothers and other national conservative groups. Environmental advocates have a long list of grievances with him, including for his lack of action to fight the growth of toxic algae on the state’s lakes and lack of support for renewable energy. Walker has overseen a “failure of state government” to care for the environment, wrote Spencer Black, a former Democratic state legislator. “We need a governor who will help, not hinder, efforts to keep our waters clean and our summers enjoyable.”

Evers has said he will improve environmental protection and take steps to better develop the clean-energy economy if elected. On those issues, and on others, he argues that he will bring common sense and a clear departure from Walker. More so than most other governor’s races, this is a referendum on an incumbent.

Short Takes

In Illinois, venture capitalist J.B. Pritzker, a Democrat who has embraced a 100 percent renewable energy commitment, has a commanding lead in his bid to unseat GOP Gov. Bruce Rauner, viewed as the most vulnerable incumbent Republican governor.

Most political odds-makers see New Hampshire‘s Republican Gov. Chris Sununu as likely to keep his seat, although his lead over former state Sen. Molly Kelly shrunk this summer. In June, Sununu vetoed bipartisan legislation to incentivize biomass and solar energy. Kelly, who sponsored the state’s first net metering bill in 2013, has called for prioritizing renewable energy and efficiency.

In Ohio, Republican contender Mike DeWine, who has been an elected official for decades, including a U.S. senator, has said little about his stances on energy and environment issues. But his record includes votes in the Senate against oil drilling in the Alaska National Wildlife Refuge and for repeal of oil company tax credits, allowing him to position himself as a moderate, as outgoing GOP John Kasich did. Democrat Rich Cordray, a former attorney general and the first director of the Federal Consumer Protection Bureau, has noted that Ohio fell behind on clean energy when its legislature halted renewable energy targets from 2014 to 2016. Cordray, who has pledged to double Ohio’s renewable energy and energy efficiency targets by 2025, is running neck-and-neck with DeWine.

Editor’s note: This story has been corrected to show that former state Sen. Molly Kelly is competing against Gov. Chris Sununu in New Hampshire.