By EVAN PEREZ

Eric Holder has spent much of his first year as attorney general trying to reverse a series of Bush administration policies. But the controversies provoked by his decisions threaten to derail his career, just as the original policies undermined the career of one of his recent predecessors.

From detainee trials to CIA interrogation programs to the role of special prosecutors at the Justice Department, Mr. Holder has been assailed from the left and right for his performance as the nation’s top law-enforcement official. A year into Mr. Holder’s tenure, one former ally is wielding comparisons to former Attorney General Alberto Gonzales, a lightning rod for the left over the treatment of terror suspects, who was ultimately drummed out of office in 2007 over the firings of U.S. attorneys.

Mr. Holder is set to be reversed by the White House on a top initiative—his proposal to try Khalid Sheikh Mohammed and the other alleged Sept. 11 plotters in civilian court in New York. The White House is close to a decision to put the detainees through military commissions instead.

The right is critical of Mr. Holder’s decision to release Bush-era memos on the Central Intelligence Agency’s interrogation program; his appointing a prosecutor to review possible wrongdoing by CIA officers; his overseeing plans to close the Guantanamo Bay prison; and his handling of the Christmas airline bombing suspect.

For the left, Mr. Holder hasn’t gone far enough. Some fault him for not punishing the former Justice lawyers who wrote the CIA memos, for adopting legal positions similar to the Bush administration, and for bungling the sales pitch in New York for the 9/11 trial.

Mr. Holder has decided to appoint Chicago U.S. Attorney Patrick Fitzgerald to investigate a separate detainee matter, according to an administration official, which will likely reignite a whole new area of controversy. Mr. Fitzgerald will examine whether defense attorneys shared photos of CIA officers involved in interrogations with Guantanamo detainees.

A senior White House official says the president stands behind Mr. Holder, and that the 9/11 trial decision has become “overdramatized and oversimplified.” The president isn’t “reversing” Mr. Holder, but rather dealing with the reality that Congress is threatening to block the Guantanamo closure, the official said.

Mr. Holder declined to be interviewed. Matthew Miller, a Justice spokesman, said many of the department’s biggest controversies this year were held over from the prior administration. “There is no way to make everyone happy dealing with those issues, and if you did, it probably means you did something wrong,” he said.

The maelstrom has prompted former allies to question whether Mr. Holder can emerge undamaged. Anthony Romero, executive director of the American Civil Liberties Union, who drew the comparison with Mr. Gonzales, said the president’s expected decision on military commissions “would leave the Justice Department on its knees. It’s hard to imagine how the attorney general would have the strength and credibility to make future hard decisions.”

Inside his own department, some career prosecutors and political appointees believe the failure to win local support in New York for the 9/11 trial has damaged the Justice Department’s standing.

Mr. Holder hasn’t helped himself with gaffes in public comments. A few days after taking office, he said the U.S. was a “nation of cowards” on race issues. President Barack Obama disavowed the comment. At a November Senate hearing, Mr. Holder fought back against criticism of the decision to seek civilian trials for terror suspects by almost guaranteeing a guilty verdict, saying that “failure is not an option.”

Sen. Jeff Sessions of Alabama, the top Republican on the Senate panel, who voted for Mr. Holder’s confirmation in February 2009, said the attorney general needed to “restore the confidence of the Congress and even the president.”

Democratic Sen. Patrick Leahy of Vermont said he supported Mr. Holder’s decision on the 9/11 trials. “I have always found Attorney General Holder to be smart, honest and forthcoming.”

A senior Democratic congressional aide said Mr. Holder was given little backing from the White House, which wanted to save the president’s political capital for health care.

Jamie Gorelick, former deputy attorney general and who advised the Obama campaign, said that Mr. Holder is “being punished incorrectly for the president’s involvement in this decision. This was not a decision that should have rested solely with the Justice Department.”

The senior White House official disputed the notion that the president has “saved his powder” to the detriment of Mr. Holder. The official noted that the president took heavy criticism for signing executive orders on Guantanamo and interrogation practices, among other moves.

Mr. Holder has come back before. In 2001, Mr. Holder attracted heavy criticism for failing to prevent President Bill Clinton’s controversial pardon of fugitive billionaire Marc Rich. Mr. Holder told the Washington Post at the time: “I’m done. Public life’s over for me.”

Write to Evan Perez at evan.perez@wsj.com