A few days after Rahm Emanuel resigned as White House chief of staff in October, I stopped by the Justice Department to see Eric Holder. I had been meeting with the attorney general periodically for about a year (since he was named one of GQ's Men of the Year last December), and I knew from our conversations, as well as from Holder's friends and family, that the last few months had been a bumpy ride. But I also knew that many of Holder's frustrations on the job could be linked to his thorny relationship with Emanuel. I wondered if things were looking up.

On the fifth floor of the Justice building, I took a seat at the long table outside Holder's office and was studying a portrait of Bobby Kennedy on the wall when Holder bounded into the room with a grin, slapped my hand into a shake, and said, "How you doing, man? Are you avoiding me?"

Up close, the attorney general is very different from the brisk and prosecutorial figure one finds on daytime C-SPAN. There is something almost whimsical about him, some half-hidden smile that always seems to linger near the corner of his mustache, as though he is watching the world from one step away.

Since his appointment in February 2009, Holder has become a vanguard for the administration's progressive wing. He has promised to end the policy of indefinite detention at Guantánamo by prosecuting some of its most notorious detainees; to investigate torture by the CIA; and to revitalize the department's most neglected offices, like the long-suffering Civil Rights Division. He has even tried to extend his influence beyond the DOJ, declaring his opposition to the death penalty and gun rights despite a constitutional obligation to enforce both.

Naturally, all of this has made Holder a favorite target of the right, and in the buildup to this month's election, the attorney general became a wedge issue unto himself, with his name plastered on Tea Party posters, newspaper ads, and television commercials. Yet Republicans may be the least of Holder's problems. Even as he has rankled the right, he has also alienated many of his allies in the administration—and none more visibly than Emanuel, whose relentless deal-making has clashed with Holder's principles time and again.

Of course, the job of any attorney general straddles a unique and tipsy political fulcrum: On the one hand, he is a member of the president's team, expected to share his political goals. On the other, he is the nation's top cop, required by oath to leave politics at the door. The balance between these can be difficult to strike, and the surest sign of an independent AG is often the irritated White House six blocks away. Still, Holder is a special case. Inside Obama's West Wing, Emanuel's hostility toward Holder has become so pitched at times that the president has had to intervene. "Occasionally, Rahm would cross the line about Eric," says a source with access to White House deliberations, "and the president would tell him, 'Rahm, knock it off.' " Inside Holder's circle of advisers, the frustration with Emanuel has been equally palpable. When I asked the attorney general's closest friend, Steve Sims, a man Holder describes as his "consigliere," about the political pressure emanating from Emanuel's office, Sims, who had been relaxing on the sofa of his Chevy Chase home, jumped from his seat and shouted, "They need to shut the fuck up and let him do his job! He is not a political animal!" And when I asked Holder's brother, Billy, about Emanuel, he sighed deeply and shook his head. "Man, that guy…" he sputtered. "That guy's an animal. He's a beast."