“It’s possible only because of the Climate Commitment Act,” Inslee said, citing a program that works to cut pollution while raising money for investments that address climate change. “That was the source. It’s the only way we’re able to do this.”

Inslee made similar remarks as he visited a salmon habitat restoration project and then test-drove a car from an all-electric co-op rideshare company’s fleet, part of a blitz by the three-term Democrat in recent months to defend the biggest climate achievement of his tenure amid a fierce repeal effort led by conservatives. Inslee, who isn’t seeking a fourth term, has appeared at more than a dozen projects funded by the law and on his personal time put his name to a flurry of emails, texts and calls to voters.

Behind the repeal effort is Let’s Go Washington, a group primarily bankrolled by hedge fund executive Brian Heywood that submitted more than 400,000 signatures from Washingtonians to get a vote on the November ballot. They argue that the law has helped push up gas prices that currently are third-highest in the nation.

Repeal would sink Washington’s plans to link up its carbon market with others, and could be a blow to its efforts to help other states launch similar programs. And for Inslee — who put climate front and center during his brief presidential campaign in 2019 — repeal would be an especially gut-wrenching loss.

He talked of a carbon pricing program as soon as he took office, and recommended the Legislature cap emissions in 2014. It wasn’t until 2021, four years after Democrats had won control of both legislative chambers, that the CCA was approved and enthusiastically signed by Inslee.

Washington was the second state to launch such a program, after California, with annual targets that start especially stringent and aim to cut emissions by almost half, compared to 1990 levels, by the year 2030.

In February 2023, the state held its first quarterly emissions allowance auction for businesses that emit at least 25,000 metric tons of carbon dioxide or the equivalent — also known as C02e. Businesses like BP must purchase allowances based on their total emissions, with one allowance equaling one metric ton of C02e. Each year, the allowances available go down.

The auctions have raised more than $2 billion, with the money used for everything from transportation to education. Inslee recently announced that $52 million from the program would go to tribes to respond to climate change.

But from the beginning, the issue of gas prices has rankled some Washingtonians. Inslee promised the program would have a negligible effect on gas prices while making huge investments in key climate programs. But the campaign to overturn it says the CCA has increased costs from 43 to 53 cents per gallon, citing the conservative think tank Washington Policy Center. Gas has gone as high as $5.12 per gallon since the auctions started, though it stood around $4.24 this month, according to GasBuddy.

“For Washington state commuters, those pennies are adding up to hundreds of dollars lost to a program that has not done what it was advertised to do,” Let’s Go Washington said in a statement in March.

Inslee has countered that Washington saw “dramatic swings” in gas prices long before the carbon pricing program, noting that its historic high of $5.54 came several months before the auctions started.

The win-win narrative touted by Inslee is a common one in the climate movement, said Aseem Prakash, professor of political science and founding director of environmental politics center at the University of Washington. But it’s not working because it’s become increasingly clear that there is a cost to climate transition, Prakash said.

“He’s playing defense on the cost … and that’s a losing strategy, because the narrative is now that the conservatives are saying we told you so, they’re going to impose tax on you,” said Prakash.

For some climate advocates, much more is on the line with this vote than a single state policy. Washington is in the process of connecting its carbon market with California and Quebec, which also have emission allowance auctions. This could make the market more stable and could happen as soon as next year, said Becky Kelley, senior policy advisor for climate to Inslee. Washington is also helping other states with efforts to launch similar programs.

“If this initiative passes here, it would definitely create a freeze and slow down states, maybe even the country’s action on addressing the climate crisis,” said David Mendoza, director of policy and government relations at The Nature Conservancy in Washington.

State law prohibits the governor’s office from setting up political or campaign events, so Inslee has been careful to say he would have appeared at projects funded by the climate law with or without the repeal vote. But it’s clear he cares deeply about the outcome, citing his six grandchildren when asked what repeal would mean to his climate legacy.

“I think about my grandchildren in this regard, that’s my legacy. I’m proud of that legacy. And I am committed to giving them a shot,” he said. “And they should have clean air to breathe. They should have salmon in the water. And they should not have to have forest fires in their future all the time. I care about that. That’s how I look at this issue, through the eyes of my grandchildren.”