A KEY CLIMATE TEST FOR CONGRESS…. I can understand when lawmakers are reluctant to do unpopular things. They’re politicians who seek public approval to keep their jobs, so it stands to reason they’ll take polls seriously.

It’s harder to understand when lawmakers are reluctant take steps with broad, popular support.

In advance of an expected Senate vote today on a GOP plan to stop the Environmental Protection Agency from regulating greenhouse gases, a new Washington Post-ABC News poll shows broad public support for the new oversight.

Some 71 percent of those surveyed back federal regulation of the release of greenhouse gases from sources like power plants, cars and factories in an effort to reduce global warming. The idea also had strong majority support in polls last year. […]

In the poll, Democrats and independents broadly support EPA regulation of greenhouse gases, with most strongly behind the new controls. More than half of Republicans also favor the new controls.

That last point was of particular interest. Overall, 71% of the country wants the federal government to regular carbon emissions to combat global warming — and lately, 71% of the country doesn’t agree on much. But also note that 55% of Republicans want the same thing.

And Congress still doesn’t want to act.

For that matter, “just a quarter of Americans back expanding offshore drilling in the wake of the BP oil spill,” but the entire legislative energy policy package is apparently dead because Republicans won’t allow a vote on a bill that doesn’t significantly expand offshore drilling.

It’s bewildering. The need for a comprehensive new energy policy is obvious; public demand for a comprehensive new energy policy is equally obvious; and an overhaul enjoys the support of the president and the leadership in both chambers.

And yet, Congress sems to be moving in the opposite direction, even in the midst of the worst environmental crisis in American history. Today there will be a showdown in the Senate over Republican Sen. Lisa Murkowski’s ridiculous scheme to make it impossible for the EPA to regulate greenhouse emissions. It needs 51 votes to pass, and Democrats who really ought to know better keep lining up on the wrong side.

Steve Benen

Follow Steve on Twitter @stevebenen. Steve Benen is a producer at MSNBC's The Rachel Maddow Show. He was the principal contributor to the Washington Monthly's Political Animal blog from August 2008 until January 2012.