Environmental groups are cautiously cheering the president's recent iniatives on climate change, but are warning him it won't mean a thing if he approves the construction of the Keystone XL pipeline.

The Hill:

"There is not a blanket of regulations big enough to cover the pipeline elephant in the room," said Jamie Henn of the green group 350.org. "There is nothing the administration could do to negate the impact the pipeline would have on the climate."

If Obama approves Keystone, it will provoke a "vehement reaction" from environmental groups, said David Goldston, director of governmental affairs at the Natural Resources Defense Council.

"People have speculated that a push in climate policies could be some kind of trade-off but for the environmental community there is no such trade-off on Keystone XL," Goldston said. "I don't think that's a strategy that would work in terms of the environmental movement either substantively or politically."

Environmental groups acknowledge widespread speculation that Obama will look to burnish his climate change credentials as a way to soften the blow of approving Keystone. Doing so could help several Democratic Senate candidates - most notably Sen. Mary Landrieu (La.).

But they reject any link between Keystone and Obama's recent announcements.

Dan Weiss, the director of Climate Strategy at the Center for American Progress, said he doesn't believe the administration has made a decision yet on Keystone.

"Any decision is a long way off," Weiss said. "Those who think they know what the president is going to do - it's wishful thinking. I don't believe even the president knows what he's going to do on this subject."

Midterm prospects will certainly play into the White House's calculations.

In an ideal world for the White House, executive actions on climate change would reinvigorate liberal voters while building the perception that Obama is accomplishing goals despite bitter partisanship in Washington.

"The president needs to demonstrate to voters that he's willing and able to act in the face of persistent intransigence," said Democratic strategist Tad Devine. "And he's doing so on issues the base of the Democratic Party cares deeply about, that activists who not only vote themselves but get others to participate care deeply about."

"It's about executive power," said Princeton University professor Julian Zelizer. "He's made it very clear he's going to act whether or not Congress is going to join him. It's about trying to show that he still has strength."

As to be expected, Obama's EPA has been critical of the pipeline - but has stopped well short of calling it a catastrophe. This hasn't stopped greens on both sides of the border from predicting climate Armageddon if Obama approves the pipeline.

The significance here is not so much damage done to Obama by his environmental base as it would be damage done to Democratic Senate incumbents who would face the wrath of the greens next November. But the prospect of tens of thousands of jobs may be too attractive for the president to pass up, not to mention the president's reluctance in handing the GOP an excellent issue to run on in November if he nixes the project.

Obama could delay the decision until after the 2012 election. Since he's shown a willingness to put just about any controversial issue beyoind that date, we probably shouldn't expect him to do otherwise with Keystone.