US lawmakers and the Obama administration braced for a divisive and unprecedented Thursday vote on whether to hold Attorney General Eric Holder in contempt of Congress after 11th-hour talks failed to reach a deal.

Defying calls from Democrats to scrap or postpone the vote to allow another chance for a negotiated settlement, House Speaker John Boehner insisted that "we're going to proceed," setting up a climactic election-year showdown between President Barack Obama's White House and Republican foes in Congress.

"We've given them ample opportunity to comply" with congressional requests for the Justice Department to turn over documents linked to botched gun-running Operation Fast and Furious, Boehner said.

The vote's timing ensures an extraordinary day on Capitol Hill Thursday, when all eyes will be on the Supreme Court as it rules on the constitutionality of the health care reform law, Obama's signature domestic achievement, which most Republicans want scrapped.

Should the ruling and vote not go Obama's way it could be a double blow for the president's reelection fight against Republican rival Mitt Romney.

Last week Obama invoked executive privilege for the first time to withhold documents sought by the House Oversight Committee, angering Republicans, who charged that it pointed to White House involvement in the scandal.

Boehner said White House staffers met with congressional officials Tuesday to seek a solution that would provide information to the committee while putting a halt to the contempt proceedings.

"Unfortunately, they're not willing to show the American people the truth about what happened," Boehner said.

The White House swiftly branded the move "political theater" and warned it would frustrate Americans struggling to rebound after the worst economic recession in decades.

"It is unfortunate. We hope Republicans change their mind as to what the right course of action is," White House spokesman Jay Carney said.

The House Rules Committee met to lay out formalities of Thursday's debate on contempt, while making clear the vote would go forward.

The hearing gave Oversight Committee chairman Darrell Issa, the driving force behind the investigation of the Justice Department's role in Fast and Furious, and ranking Democrat Elijah Cummings a final opportunity to present their cases.

Issa said that while the investigation had uncovered "no evidence" that Holder was involved in Fast and Furious, "he is the custodian of the documents, including those that we seek, and that is the reason for contempt."

He said he was still ready to bring a halt to the vote should the administration turn over the sought-after papers and emails.

Cummings warned that Republicans were recklessly racing toward what would be the House's first-ever contempt finding of a sitting attorney general.

"Why are we steamrolling ahead on a matter of such gravity?" Cummings asked, adding that he sent a letter to Boehner urging him to personally intervene in the matter.

Cummings later offered his cynical take on the proceedings.

"Their aim is to embarrass the president, embarrass this attorney general, and I think they figure that if they can do that, they'll be able to help Romney win the presidency," he told MSNBC.

"I think Americans will see through this and see how political it is."

Holder has testified about the scandal nine times and turned over 7,600 documents, but Issa said that's less than 10 percent of the Justice pages and emails being sought.

Members of the Congressional Black Caucus were reportedly urging Democrats to walk off the House floor in protest during the contempt vote.

But some Democrats announced they are joining Republicans in pursuing contempt, including John Barrow of Georgia.

"The only way to get to the bottom of what happened is for the Department of Justice to turn over the remaining documents, so that we can work together to ensure this tragedy never happens again," Barrow said.

Launched in Arizona by agents of the Bureau of Alcohol, Tobacco, Firearms and Explosives, Fast and Furious was a sting designed to track weapons bought by Mexican drug cartels.

But a large number of arms went missing, and two were later found at the 2010 murder scene of a US Border Patrol agent.

Issa has seized on who in government knew about the operation and when, and whether there was a Justice Department cover-up.

Boehner suggested that absent the handover of documents, the vote was the last course of action.

"We'd really rather not be here," Boehner said. "We'd really rather have the attorney general and the president work with us to get to the bottom of a very serious issue."