We’re stunned, but apparently, the days of tough talk, no action, and the symbolic, non-binding resolutions are behind us.

Today, Democratic leaders of the U.S. House of Representatives dug in their heels and set the stage for an aggressive debate over the future of the Iraq war.

At a press conference, House Speaker Nancy Pelosi (D-Calif.), flanked by Sen. Dick Durbin (D-Ill.) and House Majority Leader Steny Hoyer (D-Md.), introduced $96 billion in new supplemental spending for the Iraq war - but with major strings attached.

Notably, that the Iraqi government meet George W. Bush’s benchmarks for reform under penalty of immediate withdrawal of U.S. troops. There is also a timeline, regardless of benchmarks, for ending all U.S. deployment in Iraq.

“No matter what, by March 2008, redeployment begins,” Nancy Pelosi said.

By August 2008, it will be completed, according to this bill.

The bill would also require the Bush administration meet Pentagon standards for troop readiness in terms of unit readliness, length of time they can be deployed in Iraq, and the length of time they can stay at home before they are redeployed to Iraq.

The bill does grant George W. Bush some leeway - he will have the authority to depart from Pentagon guidelines if he provides a report explaining why.

This action is significant if only because Democratic leaders in the House and Senate have trouble getting their members — which range from far-left, anti-war liberals to conservative Democrats from states Bush won handily in 2004 — to coalesce around one plan.

Even this morning, ABC News reports, House Democratic leaders seemed not entirely clear on all the details of the bill they were introducing.

Nonetheless, this is the first real effort of the new Democratic Congress to end U.S. involvement in Iraq, in what will surely be a long and ugly and complicated fight.

What remains to be seen is whether this is anything more than symbolic - and what impact it will have on candidates from both parties in the 2008 election. What is the “right” vote on this, given the current electoral landscape? How will the bill itself fare under greater scrutiny?

Needless to say, the members of the U.S. Senate - Hillary Rodham Clinton, Barack Obama, John McCain and others - will find it hard to test the waters before stating their positions, and are under more pressure to “get it right,” as they are tied to their official voting records.

Advantage, Bill Richardson?