Among the dozen House Democrats who declined to sign a letter sent today urging Republican leaders to remove "blatantly partisan" riders from 2012 spending bills -- including energy and environmental policy limits -- a majority voted with the GOP earlier this year to strip U.S. EPA's authority over greenhouse gas emissions.

The overlap between the dozen missing from today's anti-rider letter and the Democrats who voted with every Republican on an April vote to stop EPA's greenhouse gas curbs suggests that the months-long congressional game of chicken over riders restricting Obama administration environmental efforts is likely to last until the final hours of this year's session. Government funding is set to expire Nov. 18, and senior House GOP appropriators have shown little appetite to abandon their push for handcuffs on air, water and mining regulations.

Spearheaded by House Minority Whip Steny Hoyer (D-Md.) and first circulated last week, the letter warns Speaker John Boehner (R-Ohio) against "playing politics with appropriations bills" by insisting on policy riders that "are unlikely to pass the Senate." Among the hot-button riders, Hoyer and 182 fellow Democrats added, are those that "roll back important clean air and clean water protections" (E&E Daily, Oct. 27).

Apart from House Minority Leader Nancy Pelosi (D-Calif.) and senior Democratic appropriator Norm Dicks of Washington, who received a copy, a dozen Democrats did not sign the letter: Reps. Heath Shuler, Larry Kissell and Mike McIntyre of North Carolina; Mike Michaud of Maine; Collin Peterson of Minnesota; Tim Holden of Pennsylvania; Joe Donnelly of Indiana; Kurt Schrader of Oregon; Gabrielle Giffords of Arizona; Dan Boren of Oklahoma; Nick Rahall of West Virginia; and Daniel Lipinski of Illinois.

Seven of those 12 Democrats -- Boren, Holden, Donnelly, Rahall, McIntyre, Peterson and Schrader -- also in April backed House GOP legislation that prevents EPA from regulating greenhouse gases under the Clean Air Act, perhaps the signature environmental priority of the Obama White House following the demise of the cap-and-trade climate bill.

Despite their small numbers, that handful of Democratic swing votes for EPA restrictions could keep hope alive among Republicans such as Rep. Mike Simpson of Idaho, the chief appropriator for EPA and the Interior Department, who told E&E last week that "there will be EPA riders or there won't be a [2012 spending] bill."

With upward of four dozen House conservatives at risk of bolting from an appropriations pact that aligns with the August debt-limit deal -- based on the number that defected during an initial vote on September's continuing resolution -- Simpson and fellow Republicans are likely to welcome even a handful of Democratic votes this month for a bill that features some environmental riders.

Click here to read a copy of Hoyer's complete anti-rider letter and a list of its signatories.