For the first time since the Iraq War began, the Senate has a good chance of succeeding in efforts to shift some of the conflict’s cost from the United States to Iraq.

After a series of failed attempts by Democrats to move legislation that would have compelled President Bush to change his war policies, the Senate will later this month take up the newly minted defense authorization bill, which would begin to cut the financial cord between Baghdad and Washington.

The measure would bar Pentagon spending in the coming fiscal year on major reconstruction work in Iraq and lay the groundwork for Baghdad to start paying its own military bills, as well as some of Washington’s expenses. The measure is expected to pass the Senate and crop up in the House.

Lawmakers in both chambers want the provision to be a part of the supplemental war spending bill as well, and to cover nearly all future U.S. government reconstruction spending in Iraq, not just that of the Pentagon. And they may apply its limitations to previously appropriated funds that have not yet been spent.

Fueling the measure’s advance is the growing frustration on Capitol Hill with the cost of the war to U.S. taxpayers while Iraq earns billions of dollars in revenues from record oil prices.

That seeming inequity has made restricting U.S. spending in Iraq a compelling cause for lawmakers of both parties, whatever their views on the war.

The measure is also unusual because of how it was crafted. A bipartisan group of Senate lawmakers coordinated with the White House on the Iraq reconstruction provision — instead of the Democrats going it alone as they have in the past, only to see their policy prescriptions die in the Senate or fall to Bush’s veto pen.

Against that backdrop, Republican Susan Collins of Maine, who helped write the legislation, sounded Thursday as if the measure had just been enacted.

“This is the first significant bipartisan change in our policy toward Iraq,” she exulted.

The measure was the product of senators from both parties. Democrats involved in the process included Carl Levin of Michigan, chairman of the Armed Services Committee, and panel members Ben Nelson of Nebraska and Evan Bayh of Indiana. Joining them were Republicans Collins and John W. Warner of Virginia, who called the proposal a “very positive step forward.”

The provision they crafted would ban Pentagon spending on reconstruction projects over $2 million. And it would require the U.S. government to work with the Iraqis to see if they will pay for smaller scale projects, too.

The measure would allow the United States, for now, to continue spending on Iraqi military capabilities and combined U.S. and Iraqi military operations. But the language would set in motion a process that would result in Iraqis increasingly paying for those accounts.

Specifically, the bill states that the U.S. government must “take action to ensure that Iraq funds are used” to pay for salaries, training, equipping and sustaining both the Iraqi security forces and the “Sons of Iraq,” the Sunni tribesmen who formerly fought coalition forces and now support them.

And the committee instructs that negotiations must begin with the Iraqis on an agreement to share costs for combined military operations.

Collins and others said they would push to get their Iraq spending language on the war supplemental, where the prohibition on U.S. support for major rebuilding projects would apply to all U.S. agency expenditures, not just the Pentagon’s.

And Levin said he was open to amending the defense authorization bill on the Senate floor in the same way and to apply its limitations to previous appropriations that have not yet been obligated.

The latter point is key because the Pentagon late last month notified the Senate Armed Services Committee that it was reallocating $439 million in fiscal 2007 funds for reconstruction work in Iraq.

In the House, a bipartisan consensus on the funding issue also appears to be forming. Democrat Ron Klein of Florida and Republicans Christopher Shays of Connecticut and Dana Rohrabacher of California have proposed ways to make Iraq pay more of its reconstruction and security costs.

Senators said they worked with White House officials in writing the measure. They met earlier this week with Lt. Gen. Douglas Lute, Bush’s chief war adviser on Iraq and Afghanistan on the National Security Council.

Administration officials have expressed concerns that spending restrictions might impede progress in Iraq. They have said that in many areas, Iraq lacks the administrative ability to spend its oil resources effectively.

The senators said the White House requested that the legislation authorize the president to waive its limitations if he deemed national security to be at risk. The senators rejected that plan, fearing it would enable the president to disregard the law.

“We felt very strongly that had the potential to gut our language,” Collins said.

On Thursday, White House spokesman Tony Fratto was noncommittal about the provision.

“We’ll review it and see how it affects the ability for our military to carry out their mission,” he said.

Adam Graham-Silverman contributed to this story.