Environmental groups are going to fight like hell against Republicans in the 2016 presidential election, but they have no intention of going easy on Hillary Clinton either.

As Clinton prepares to announce her campaign—a formal announcement is expected Sunday—environmental groups are preparing a series of stress tests for the Democratic front-runner, hoping to get assurances that she’ll hold their line on a host of green issues.

Climate-activist group 350 Action will hold a demonstration on Monday outside Clinton’s New York headquarters, where protesters will call on Clinton to clarify her stand on the Keystone XL oil-sands pipeline. And following the announcement, 350 Action, the Center for Biological Diversity, and other groups plan to push Clinton to take stands on other issues, including fracking and other federal financial supports for the fossil fuel industry. (The effort kicked off on Friday when more than 100 groups, including environmental-advocacy organizations such as Friends of the Earth and the Center for Biological Diversity, penned a letter to Clinton calling on her to oppose fracking.)

The groups want firm, on-the-record commitments from Clinton, hoping to hold her to green promises later in the campaign and, should she win, as the next president.

So far, they’ve gotten few explicit guarantees. Clinton has famously declined to say what she thinks of Keystone, and in the run-up to her announcement, she has said little about other environmental issues as well. Indeed, Clinton has kept largely quiet on most policy issues, save for the occasional Twitter post or statement. But for environmental groups looking for a Democrat to champion causes they’re sure Republicans won’t, the lack of explicit policy guarantees is worrisome.

“Clinton has got to tell us what she stands for,” said Bill Snape, a senior counsel with the Center for Biological Diversity. “If we’re going to be asked to trust her, then she has to verify where she stands. That’s all we’re asking, and she hasn’t yet delivered.”

The moves are part of a delicate, codependent relationship between the candidate and the environmental movement.

Green groups need Clinton (or any other Democrat) to beat the eventual GOP nominee, lest they find themselves with a president totally at odds with their stances. But they can’t afford to offer unconditional support for fear that the candidate will not prioritize their issues amid the sea of Democratic causes.

Many of the most prominent green groups, including the Sierra Club and the League of Conservation Voters, have been hesitant to criticize Clinton. But grassroots and progressive groups have long expressed concern over a Clinton 2016 run.

“I think she has a lot of ground to make up if she’s going to get enthusiastic support from the environmental world,” Bill McKibben, the founder of grassroots environmental group 350.org, said in an interview.