In its last survey of voter priorities, Gallup found that the least pressing issue on the mind of the electorate was the environment, scoring below race relations in a race for last place.  Now, with the Obama administration and Democrats on the Hill preparing to do battle over carbon emissions, Gallup’s latest poll of environmental issues shows global warming coming in last among environmental priorities:

With Earth Day about a month away, Americans tell Gallup they worry the most about several water-related risks and issues among nine major environmental issues. They worry least about global warming and loss of open spaces.

At least three in four Americans surveyed in Gallup’s 2011 Environment poll say they worry a great deal or a fair amount about contamination of soil and water by toxic waste, pollution of rivers, lakes, and reservoirs, pollution of drinking water, and the maintenance of the nation’s supply of fresh water for household needs.

Air pollution is nearly as high a concern for Americans, with 72% worried a great deal or a fair amount about it.

A little more than 6 in 10 worry about the related problems of extinction of plant and animal species and the loss of tropical rain forests. Slightly fewer worry about urban sprawl and loss of open spaces, while barely half, 51%, worry about global warming.

In fact, it only gets a 51/48, with almost as many Americans saying that they don’t worry about it much or at all.  Global warming concern has dropped twelve points since 2001, the same amount as for the loss of open spaces and just one point less than the decline in worry for the loss of tropical rain forests.  In fact, all of these issues suffered decline in concern over the past decade, with only three issues avoiding double-digit drops: water pollution, soil contamination, and species extinction.

Into this ennui charge the Democratic environmental light brigade, which seems to have lost its enthusiasm:

The Environmental Protection Agency debate lands in the Senate this week, amid the makings of a left-right coalition to mitigate the agency’s abuses. Few other votes this year could do more to help the private economy—but only if enough Democrats are willing to buck the White House.

This moment arrived unexpectedly, with Majority Leader Harry Reid opening a small business bill to amendments. Republican leader Mitch McConnell promptly introduced a rider to strip the EPA of the carbon regulation authority that the Obama Administration has given itself. Two weeks ago, Mr. Reid pulled the bill from the floor once it became clear Mr. McConnell might have the 13 Democrats he needs to clear 60.

The votes are now due as soon as tomorrow, and Mr. Reid is trying to attract 41 Democrats with a rival amendment from Senate Finance Chairman Max Baucus. The Baucus plan is a political veneer that would exempt some farms and businesses from the EPA maw but at the cost of endorsing everything else. The question for Democrats is whether their loyalties to President Obama and EPA chief Lisa Jackson trump the larger economic good, not to mention constituents already facing far higher energy costs.

Republicans see this as a big opportunity, even if they lack the votes to stop the EPA:

The Republican proposal is unlikely to get the 60 votes needed to become part of pending small-business legislation. But Democratic leaders are also expected to fall short with two competing proposals, aimed at allowing more than a dozen politically vulnerable Democrats to take a milder slap at the EPA without altogether rebuking the White House.

Either way, Republicans are eager to get Democrats on the record opposing the administration’s climate policies.

“What is clear is that Democrats themselves are looking for ways to be on the opposite side of the administration’s agenda,” said Matt Dempsey, a spokesman for Oklahoma Republican Sen. Jim Inhofe.

Inhofe and Senate Minority Leader Mitch McConnell have offered a proposal that would block the EPA from regulating greenhouse gases.

As alternatives, Democrats are offering an amendment from Montana Sen. Max Baucus that would exempt agriculture and small industrial facilities from climate rules, and another from West Virginia Sen. Jay Rockefeller that would impose a two-year timeout on regulations of stationary sources.

The Baucus and Rockefeller alternatives “are being used by Democrats as political cover,” Dempsey said. “So the question will eventually become, ‘Do these Democrats actually want to stop the [Obama] agenda, or do they just want to talk about it?’”

With climate change the least possible worry on the least concerning issue for American voters, it’s difficult to see exactly what Barack Obama and the Democrats in Congress hope to win from this debate, or from Obama’s determination to allow Jackson and the EPA to conduct more regulatory adventurism at the expense of the economy.  It looks like Obama may be losing some cover on this in Capitol Hill, and he may be forced into issuing a veto to protect his end-run around the legislative branch.  If he does, voters may well wonder why Obama’s picking a fight on an issue literally at the bottom of the bottom of the list.