U.S. Attorney General Eric Holder, center, and Senate Judiciary Committee Chairman Patrick Leahy (D-VT) arrive for a full committee hearing Tuesday on Capitol Hill. Holder faced questions about the Operation Fast and Furious investigation and his decision to order two federal prosecutors to begin criminal investigations into a series of national security leaks to the news media. (Chip Somodevilla/Getty Images)

For more than three years, Attorney General Eric H. Holder Jr. has tried to play a double role — political and apolitical at once. He has cast himself as the country’s nonpartisan top cop, but also as the Obama administration’s best weapon for a liberal view of justice.

But now, more than ever, Holder is struggling to do both jobs.

An inquiry involving the apolitical side of his position — involving a botched gun-trafficking investigation in Arizona — has made the attorney general newly vulnerable to his political opponents. Next week, a House committee could vote to cite him for contempt of Congress, accusing him of withholding information in that case.

That would be the latest in a series of setbacks for Holder, a soft-spoken former judge and close friend of President Obama. He also is facing questions about his oversight of an investigation of national security data leaked to reporters.

Holder is a lightning rod for anger in the administration — viewed by his supporters as a symbol of Obama’s ambitions and by his enemies as a symbol of the president’s aloofness and overreach.

“It’s a politicization of the department,” said Rep. Trey Gowdy (R-S.C.), a member of the House Oversight and Government Reform Committee, which is considering the contempt finding. “If he were a Republican AG and he were using that office to advance a political agenda, I would be just as critical of him.”

In a tense hearing last week on Capitol Hill — one of nine that Holder has attended over the past year — Gowdy made this argument to him: “I don’t think the attorney general for the United States of America should have any political ideology whatsoever.”

Holder responded by saying he wasn’t the first to plunge the Justice Department into political debates.

“Let’s ask,” he said to Gowdy, mentioning President George W. Bush’s strongly conservative choice for the office. “Do you think John Ashcroft was a conservative?”

Ashcroft, Bush’s first attorney general, was criticized by liberals for allowing more extensive government surveillance after the attacks of Sept. 11, 2001, and urging harsher interrogations of suspected terrorists. A successor, Alberto R. Gonzales, resigned after an investigation of politically motivated removals of U.S. attorneys on his watch.

Under Holder, the Justice Department has recorded a number of law enforcement successes and uncovered several alleged plots by terrorist groups. Justice officials have recouped nearly $4.1 billion in health-care fraud.

But the department has also inserted itself into several domestic controversies, often taking on state laws backed by conservatives — such as statutes requiring voters to show photo identification at the polls. Justice officials sought to block such laws in Texas and South Carolina, saying they harmed minority groups.

Holder’s department also sued Arizona over its immigration law, saying it might lead to racial profiling. His civil rights division joined the inquiry of the highly charged Trayvon Martin shooting case in Florida. And last month, the department sued Sheriff Joe Arpaio of Arizona’s Maricopa County, accusing him of violating the civil rights of Hispanics.

Holder, 61, had been a partner at a Washington law firm and served as U.S. attorney for the District. In an interview last year with the New York Times, he said that some of his critics had made him a proxy for Obama because of their friendship and because Holder is also black.

These critics wanted “a way to get at the president because of the way I can be identified with him,” Holder told the Times.

Rep. Elijah E. Cummings (Md.), the top Democrat on the oversight panel, said Holder can come off as a less polite version of Obama.

“He has no problem with being very blunt in telling you when you’re not accurate, and he does not deal with criticism in the way that perhaps the president would,” Cummings said. “I know one thing: I’m appalled at the way they treat him.”

Earlier in Obama’s tenure, Holder clashed with some White House aides. They objected to his announcement that alleged terrorist mastermind Khalid Sheik Mohammed would be tried in New York, and Obama later reversed it. They criticized a speech on race in which Holder said that the United States is “a nation of cowards.”

This week, White House press secretary Jay Carney said the president has “absolute confidence” in Holder.

The attorney general’s most immediate trouble stems from an operation named after a popular movie: Operation Fast and Furious. Starting in 2009, the Bureau of Alcohol, Tobacco, Firearms and Explosives chose not to stop more than 2,000 guns from hitting the streets.

The agency’s plan was to track the firearms and eventually prosecute those who shipped them and bought them. Many guns disappeared, and some later turned up at crime scenes, including at the fatal shooting of a Border Patrol agent.

Holder stopped the tactic and ordered an inquiry by the Justice Department’s inspector general. But Republicans say that, since then, he has not fully complied with a congressional investigation and has withheld documents that detail the department’s internal decision-making.

“We basically sign his paycheck with our appropriations,” said Rep. Blake Farenthold (R-Tex.), another member of the committee. “When we ask for information, they ought to be forthcoming, or they ought to come up with good reasons not to give it to us.”

At a hearing Tuesday, Holder offered to meet personally with any Republican to try and resolve the conflict, and called the Republican stance “political gamesmanship.”

Already, more than 100 GOP lawmakers have called for Holder to resign. They say his personality, which can be quietly defiant, has not helped him.

“It’s just a smugness there that, on a personal level, rubs me the wrong way,” Farenthold said.

On Wednesday, the oversight committee is scheduled to vote on a contempt-of-Congress finding. The next step would be a vote by the full House. If it passed, the U.S. attorney for the District would have to decide whether to prosecute Holder, his boss.

While Holder is defending himself from the political investigation, there is an “opportunity cost” to his nonpolitical work, said Robert Raben, an assistant attorney general in the Clinton administration. He noted that Holder and his top aides are tied up with congressional inquiries, taking them away from their work on voting rights, the environment, antitrust issues and civil rights.

“That’s the number one damage,” said Raben, a former colleague of Holder’s and now a Washington lobbyist.

If these challenges pass, Holder will have another one waiting for him. After a clamor over the possible leaks to reporters of classified information about U.S. military and intelligence operations, he names two federal prosecutors last week to lead two investigations.

Congressional Republicans called on him to appoint a special counsel instead, saying that the two U.S. attorneys cannot be independent because they work for him.

At the bitterly contentious Senate hearing this week, Holder reflected on his tenure: “It’s been a tough job. . . . I’ve been criticized a lot for the positions I’ve taken. I’ve lost some. I’ve won more than I’ve lost. And I’m proud of the work I’ve done. . . . What my future holds, frankly, I’m just not sure.”