After largely avoiding the subject since the 2003 invasion of Iraq, lawmakers are suddenly confronting the issue of President Bush’s handling of the war. The start hasn’t been pretty.

Political stunts by both parties have created an air of acrimony that is infecting the parties’ entire agendas. The bitterness reached a new high – or a low – on Friday when House Republicans forced a late-night vote on a resolution for immediate withdrawal of U.S. forces.

The resolution failed, 3-403, but only after members nearly came to blows when GOP newcomer Jean Schmidt, Ohio, suggested veteran Democratic military hawk John Murtha was a coward.

“Iraq is now a cloud over everything,” said Stuart Rothenberg, a non-partisan political analyst specializing in Congress. “It’s the 800-pound gorilla in the room.”

“I feel like every morning I wake up, get a concrete block and have to walk around with it all day,” said first-term Sen. Jim DeMint, R-S.C., who came to the Senate with an ambitious agenda to overhaul Social Security and the tax code. “We can’t even address the issues.”

After simmering on Congress’s back burner for months, the Iraq debate has eclipsed every other issue in the capital, slowing the progress on some matters while completely stopping progress on others. The GOP-led House and Senate are struggling to pass major tax legislation, an extension of the USA Patriot Act and a sweeping budget-cutting bill. Bush’s top 2005 domestic agenda – revamping Social Security – has sunk from sight, and more recently his bipartisan panel on tax reform barely made a ripple when it issued recommendations.

GOP leaders view items such as the Patriot Act and the budget as too vital to fail in the end, but every endeavor is now made more difficult by the fracturing over Iraq – and just as the 2006 congressional elections begin to loom. Republicans have lost their anchor of the past five years – Bush’s popularity – while Democrats still struggle to find their voice on the war. Both sides cannot dally for long, said Peter Hart, a Democratic pollster.

“Iraq is now the dominant issue that is affecting voters, and it’s affecting Bush’s ratings,” Hart said. “The public has reached a firm, fixed position on Iraq, and it’s not going to change: This is not going to come to a successful conclusion, so how do we figure out how to get out of Iraq?”

Until recently, only Democrats seemed to struggle to find their voice on Iraq, as Republicans were virtually united in backing Bush’s policies. But when the 2,000th U.S. military death there coincided with troubling revelations about pre-war intelligence and Bush’s plunging approval ratings, Republican cohesion began to fray.

Political developments in Iraq, such as the adoption of a new constitution, cannot overcome the impression left by the daily reports of suicide bombers and the milestone of the 2,000th U.S. serviceman lost, pollsters and political analysts say.

Public opinion has, in turn, emboldened Democrats to sharpen their attacks, and it has freed some Republicans – especially Northeastern moderates – to chart a new political course that separates them from the White House but wreaks havoc on the GOP’s legislative agenda.

“The central new development is the decomposition of the president’s support in Congress,” said Ross Baker, a Rutgers University congressional expert. “I think there is a very acute realization on the part of Republicans that they no longer can hitch their careers to his popularity. That, combined with the new aggressiveness by the Democrats, means you’re seeing basically a Bush agenda that is largely being derailed.”