With the National Rifle Administration demanding a "yes" vote and African-American lawmakers vowing to walk out of the chamber, the House moved Thursday toward holding Attorney General Eric Holder in contempt of Congress in a document dispute related to a bungled gun-tracking operation.

Republicans had the votes to make Eric Holder the first sitting attorney general to be held in contempt. They cited Holder's refusal to meet Republican demands to hand over _ without any preconditions _ documents that could explain why the Obama administration initially denied that a risky "gun-walking" investigative tactic was used in Operation Fast and Furious, which allowed hundreds of guns to be smuggled from Arizona to Mexico.

The vote on a criminal contempt resolution will send the matter to the U.S. attorney for the District of Columbia, who is under Holder. A separate vote on civil contempt will allow the House to go to court in an effort to force Holder to turn over the documents the Oversight and Government Committee wants.

In past cases, courts have been reluctant to settle disputes between the executive and legislative branches of government.

The NRA urged House members to vote for contempt, contending the administration wanted to use Operation Fast and Furious to win gun control measures. Democrats who normally support the NRA but who vote against the contempt citations would lose any 100 percent ratings from the group.

That could affect whether they get endorsements from the powerful organization, particularly if Republican opponents surface who are strong NRA backers.

The 42-member Congressional Black Caucus said its members would walk out and refrain from voting. Democratic leader Nancy Pelosi of California said she was joining the boycott.

"Contempt power should be used sparingly, carefully and only in the most egregious situations," a letter from the caucus to House members said. "The Republican leadership has articulated no legislative purpose for pursuing this course of action. For these reasons, we cannot and will not participate in a vote to hold the attorney general in contempt."

Members of the Hispanic, Asian Pacific American and progressive caucuses said they also would not vote.

The dispute is both legal and political. Republicans asserted their right to obtain documents needed for an investigation of Operation Fast and Furious _ focusing on 10 months in 2011 after the Obama administration initially denied guns were allowed to "walk" from Arizona to Mexico. By year's end, the administration acknowledged the assertion was wrong.

President Barack Obama asserted a broad form of executive privilege, a legal position designed to keep executive branch documents from being disclosed. The assertion ensures that documents will not be turned over any time soon, unless a deal is reached between the administration and congressional Republicans.

In debate, however, Republicans framed the issue as the need for closure for the family of Brian Terry, a Border Patrol agent killed in December 2010 in a shootout with Mexican bandits. Two guns from Fast and Furious were found at the scene.

Democrats said the contempt issue was a political stunt to embarrass the Obama administration in an election year, and added that holding the attorney general in contempt will do nothing to bring closure to Terry's family.

Rep. Jackie Speier, D-Calif., said the contempt motions were "Fast and foolish, fast and fake."

Rep. Rich Nugent, R-Fla., took the opposite view, arguing, "A man died serving his country, and we have a right to know what the federal government's hand was in that."

Rep. Jim McGovern, D-Mass., said Republicans picked an odd day to schedule the contempt vote.

"I find it interesting that the Republican leadership has scheduled this nonsense for the floor today when it is certain to be buried under the avalanche of news and reaction to the Supreme Court's health care decision," he said.

For the past year and a half, some Republicans have promoted the idea that Holder and other top-level officials at the Justice Department knew federal agents in Operation Fast and Furious had engaged in gun-walking.

Two of Holder's emails and one from Deputy Attorney General James Cole in early 2011 appear to show that they hadn't known about gun-walking but were determined to find out whether the allegations were true.

"We need answers on this. Not defensive BS. Real answers," Holder wrote.

The Justice Department showed the e-mails on Tuesday to Republican and Democratic staffers of the House Oversight and Government Affairs Committee, whose chairman is Rep. Darrell Issa, R-Calif., in an effort to ward off the criminal contempt vote against the attorney general.

The full contents of the emails were described to The Associated Press by two people who have seen them. Both people spoke on condition of anonymity because they were not authorized to speak about them publicly.

Holder has refused to turn over these and other communications unless the oversight panel dropped its subpoena for the records _ a condition unacceptable to Issa.

The department withdrew the Feb. 4 letter denying gun walking took place on Dec. 2, 2011, after documenting what had taken place not only in Operation Fast and Furious, but in three other gun-walking operations going back to 2006.

In Operation Fast and Furious, agents of the federal Bureau of Alcohol, Tobacco, Firearms and Explosives in abandoned the agency's usual practice of intercepting all weapons they believed to be illicitly purchased. Instead, the goal of the tactic known as "gun-walking" was to track such weapons to high-level arms traffickers who had eluded prosecution and to dismantle their networks.

Gun-walking long has been barred by Justice Department policy, but federal agents in Arizona experimented with it in at least two investigations during the George W. Bush administration before Operation Fast and Furious. The agents in Arizona lost track of several hundred weapons in that operation.

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Associated Press Writer Pete Yost contributed to this report.