Holder faces House contempt vote on gun probe WASHINGTON (Reuters) - U.S. Attorney General Eric Holder faces a contempt vote by the House of Representatives on Thursday in a dispute involving a botched gun-running probe, and the chamber's top Democrat, Nancy Pelosi, said some in her party may line up with Republicans against him. The Republican-led House is to vote on whether to charge the nation's top law enforcement officer with contempt of Congress related to his withholding of documents in a gun-running sting operation on the U.S.-Mexico border code named "Fast and Furious." The operation was run by the Bureau of Alcohol, Tobacco, Firearms and Explosives, which is part of the Justice Department that Holder heads. Speaking at a Reuters Washington Summit, Pelosi called the move against Holder "one of the most irresponsible" acts she has witnessed in Congress, but some Democrats are feeling pressure to vote with Republicans. The National Rifle Association, which wields great influence with both parties in Washington, has put members on notice that the contempt vote is considered a "gun issue" with repercussions for anyone voting "no." Pelosi said she tells members that if the Republicans "are acting politically, you may have to react politically." She said Holder has turned over thousands of documents, but that Republicans are pushing for more merely to try to undermine his efforts to stop voter suppression. "They want the attorney general to be tied up," she said. This is such a canard. She cited a recent hearing in which Republican Senator John Cornyn called on Holder to resign for resisting the House probe at the same time he "blocks states from implementing attempts to combat voter fraud." Pelosi was referring to lawsuits brought by the Justice Department against some states - most notably Florida - accusing them of violating voting rights laws. "The whole reason that they want him to resign is because he's looking into voter suppression," Pelosi said. It's all connected. The Supreme Court decision, suffocate the system with money, suppress the vote, poison the debate. Fast and Furious, devised by law enforcement officials in Arizona, was aimed at tracing the illegal flow of guns from the United States over the border with Mexico where they were suspected of falling into the hands of violent drug cartels. The operation went awry when agents lost track of many of the weapons and at least one was found at the murder site of a U.S. Border Patrol agent. House Republicans say they are trying to determine whether high-ranking administration officials knew the true nature of Fast and Furious but withheld it from congressional investigators. The House Oversight and Government Reform Committee is seeking documents which Holder declined to provide after months of negotiations with Republican leaders who control the House, saying he had already turned over thousands of pages relating to the operation. Holder has said that the additional materials sought by the committee are covered by the doctrine of executive privilege, historically invoked by presidents to protect the confidentiality of communications within their administrations. Last week, the Oversight and Government Reform Committee, in a party-line vote, passed a measure to charge Holder with contempt of Congress. Democrats have accused Republicans of stoking a scandal for political gain to hurt Democratic President Barack Obama before the November 6 election. We'd really rather have the attorney general and the president work with us to get to the bottom of a very serious issue," House Speaker John Boehner said on Wednesday, referring to the vote by the full House. Boehner said Republicans have given the administration "ample opportunity" to comply with the committee's requests for documents. It's an unfortunate place where we are," he said. Besides voting on the contempt charge against Holder, the House also is planning to consider a second resolution to ask U.S. courts to force him to turn over the documents. Editing by Will Dunham, Fred Barbash and Christopher Wilson