On March 31, Hillary Clinton held a rally at SUNY Purchase College, just north of New York City. As she worked the rope line after her speech, she stopped to shake hands with supporters and was confronted by a young activist.

“Thank you for tackling climate change,” the woman, Eva Resnick-Day, said. “Will you act on your words and reject future fossil fuel money in your campaign?”

Though Clinton had faced the question many times before, she bristled. Over the blare of Rachel Platten’s “Fight Song,” she raised her voice and pointed at Resnick-Day. “I am so sick of the Sanders campaign lying about me,” Clinton said, in a videotaped moment that went viral. “I’m sick of it.”

Resnick-Day is an organizer for Greenpeace, and an activist from 350 Action, an offshoot of Bill McKibben’s 350.org, shot the video of the encounter. The two groups had coordinated during the primary in sending “bird doggers” to campaign events throughout the country to question Clinton and other candidates on climate positions. Now that the general election contest has been decided, Resnick-Day says she won’t bother with such tactics. “It’s about continuing to find opportunities where Clinton can bolster her climate and democracy platforms,” she says, and “really trying to use the leverage now of all these millennials who want climate action.”

She projects optimism, but “these millennials”—including Resnick-Day—overwhelmingly backed Bernie Sanders in the primary. Now they, along with other staunch environmentalists, must settle for Clinton, or back Jill Stein’s hopeless Green Party bid. It’s a disappointing end to a race that energized and raised hopes on the environmental left.

“Right now, there’s a little bit of grief,” admitted Karthik Ganapathy, who returned to 350 communications after a stint on the Sanders campaign communications team, “a little bit of thinking, ‘What comes next?’”

It’s a question without a concrete answer.

Many environmentalists are wary of Clinton because of her “mixed record,” as Kelly Mitchell, a campaign director at Greenpeace, calls it. Only recently has Clinton showed a commitment to several of the movement’s top concerns, an evolution likely prompted by Sanders’s primary challenge.

In 2010, as secretary of state, Clinton said the Obama administration was inclined to approve Keystone XL. Then, in the early stages of her candidacy, Clinton refused to take a stance on the pipeline, insisting she would do so when she took office. That wasn’t enough for activists, who continued to question Clinton throughout last summer. In September, they got the answer they were looking for. “I think it is imperative that we look at the Keystone pipeline as what I think it is, as a distraction to the important work we have to do on climate change,” she said at a campaign event in Iowa. “Therefore I oppose it.”

As secretary of state, Clinton was also a strong proponent of the Trans-Pacific Partnership, which she described as “innovative,” “cutting-edge,” and “high-quality.” Environmentalists oppose the deal because they say it could increase U.S. exports of natural gas (fueling the fracking industry) and allows corporations to challenge government environmental regulations. As a candidate, Clinton withheld her position until the Obama administration finalized the agreement in October. Shortly thereafter, she came out against it.

For activists who have spent their careers fighting America’s reliance on fossil fuels, and who saw Sanders come out early against Keystone XL and the TPP, Clinton’s reversals still feel fresh. But as she steadily gained delegates, she steadily gained endorsements. She now has the explicit backing of The Sierra Club, the League of Conservation Voters Action Fund, the Natural Resources Defense Council Action Fund, and wealthy activist Tom Steyer—the environmental establishment, in other words.

Will the green lefties come around, too?

The grieving began in earnest on June 6, on the eve of the California primary, when the Associated Press declared Clinton the presumptive Democratic nominee.

“For 24 hours I was very angry with the Associated Press,” says R.L. Miller, president of green PAC Climate Hawks Vote Political Action and the chair of the California Democratic Party’s environmental caucus. Miller says that as a Californian she was concerned about whether declaring a nominee would repress voter turnout.

In a “climate primary” of Climate Hawks Vote members, Bernie Sanders received 92 percent of the vote. Miller calls Clinton “mediocre” on climate, and says she won’t get her group’s endorsement, but Climate Hawks Vote will advocate for Clinton over Trump. “We don’t endorse every candidate who is a ‘B’ or ‘C’ candidate on climate just because they’re running against a Republican,” she says.

But Miller says there are signs that Clinton could become a climate hawk, like her solar plan, and she plans to vote for Clinton in the general election.

“I definitely want to defeat Donald Trump,” she says.

Others remain uncommitted. Former U.S. representative Cynthia McKinney, who ran for the Green Party nomination in 2008, last week tweeted a story in The Hill about Clinton’s support from green groups, and asked, “Are they freaking out of their minds?” James Handley, a policy analyst with the Carbon Tax Center and a former EPA attorney, tweeted the same article, adding, “#Hillary climate policy = ineffective subsidies, mandates, regs. #Trump really ++worse?”

For many greens, hope remains in the crafting of the Democratic platform at the convention in Philadelphia.

“It’s great that we have a Democratic Party that endorses the climate science,” says Erich Pica, president of Friends of the Earth Action, which endorsed Sanders. “Unfortunately, you can endorse the science and recognize the urgency, but if your policies and your platform aren’t commensurate with what you acknowledge, I think you can be accused of a form of climate denialism.”

Perhaps sensing this “lingering distrust,” as Ganapathy describes it, the Clinton campaign tried in recent days to assuage the green left’s concerns. Last week, at the League of Conservation Voters’ annual Capital Dinner—a hot, pricey ticket for D.C. greens—Clinton campaign chair John Podesta suggested there was little daylight between his boss and Sanders. “In the Democratic primaries, we had two great candidates, two climate warriors who didn’t so much disagree on the urgency and the scope and the ambition of tackling the climate problem, but on the details and best programs to make progress,” he said. “We have to make sure climate denial does not find a home in the White House.”

Most Sanders environmentalists seem to agree, however grudgingly. After all, Stein is only on the ballot in 21 states and D.C., and the choice between Trump and Clinton—Handley’s tweet notwithstanding—is clear. Trump claims global warming is “bullshit” that “was created by and for the Chinese.” Perhaps this is why some green lefties who are grieving over Sanders’s loss have already reached the fifth stage: acceptance.

“I wouldn’t say I’m disappointed myself—I would say that I’m resigned,” said Miller. “Bernie had a good run. It’s over.”