Environment Colorado is dropping $400,000 on staff this summer to knock on doors in all seven congressional districts, but the topic of their discussions isn’t next year’s election and who voters should choose. The Denver-based advocacy group wants to talk about Colorado Sens. Cory Gardner and Michael Bennet.

But mostly they’re pressuring Gardner, a Republican from Yuma, to oppose the Trump administration’s rollbacks on environmental regulations. Bennet is a Democrat, so of course he stands with Environment Colorado, at least close enough for politics.

But as far as consequences, Bennet doesn’t stand for election again until 2020, and Bennet, who was re-elected in November, has until 2022 before his next election.

“It’s really focused on the Senate, because the Senate is where we have the best chances of stopping some of these environmental rollbacks,” Garrett Garner-Wells,  Environment Colorado’s director, tells Colorado Politics.

The campaign aims to reach 60,000 Coloradans as part of a national effort  in 22 states and the District of Columbia, according to Environment Colorado.

Gardner’s office did not immediately respond to a request for a reply about the campaign, but I’ll update this blog at the top if they decide to weigh in. Coordinated liberal protests over a variety of Republican measures are a part of the office’s daily onslaught and geared to pick a fight.

Gardner has a mixed record on environmental issues from both sides. He’s a supporter of public lands, even pushing to relocate the Bureau of Land Management headquarters to Colorado, but has an 11 percent lifetime score with the League of Conservation Voters.

The Trump administration announced a repeal of the Waters of the United States rule this week, and Gardner said the regulation’s harmful impact on the state’s farmers, ranchers and small business owners couldn’t be overstated.

“Colorado’s agriculture community is already facing hardship and it is welcome news that this over burdensome regulation will never go into effect,” he said in a statement. “This decision was necessary to protect Colorado’s economy and put a stop to Washington’s unconstitutional takeover of our state’s rivers, streams and local waterways.”

Garner-Wells said the door-knocking started at the end of May and extends through August.

“Here in Colorado, our senators could not be more different,” he said in a statement. “While Sen. Bennet has voted consistently against rollbacks to environmental protections, Sen. Gardner has done the opposite. But it doesn’t have to be that way.”

Garner-Wells said special interests, the Trump administration and some congressional members see environmental safeguards as an expensive luxury.

“I’m confident our campaign will help galvanize the public, and make sure people’s voices are heard loud and clear.” he said. “Together, I know we’ll find the way to protect the environmental values we share and the places we love. Our families and our future depend on it.”