Michael B. Mukasey has a well-earned reputation for straight talking, but his nomination for United States attorney general is in trouble unless he flatly acknowledges that waterboarding is torture and rejects it.

In his appearance before the Senate Judiciary Committee, he began with a clear denunciation of torture as not only illegal but also “antithetical to everything this country stands for.” But the next day, when asked specifically by Sen. Sheldon Whitehouse, D-R.I., if the simulated drowning practice was constitutional, he turned evasive and gave a delphic reply. He said, “I don’t know what is involved in the technique. If waterboarding is torture, torture is not constitutional.”

Mr. Mukasey’s written response to 495 questions from the committee was equally troubling on this issue. He wrote that while waterboarding was repugnant to him personally, “hypotheticals are different from real life and in any legal opinion the actual facts and circumstances are critical.

Here are the actual facts: Waterboarding, a technique where a suspect is made to feel he is drowning, is forbidden as an interrogation technique by the U.S. military field manual. The Central Intelligence Agency and other U.S. government entities are reportedly using it, however, against detainees in the war on terror.

Less than two weeks ago, leading Democrats were hailing the nomination as showing a new attitude in the Bush White House and a new respect for the rule of law. But Mr. Mukasey’s evasiveness on crucial issues dear to the Bush administration has aroused doubts even among some Republicans.

Sen. Olympia Snowe, a member of the Intelligence Committee, told Fox News this week that waterboarding was torture. “I don’t see why he couldn’t answer the question more straighforwardly,” she added.

There are other issues. Sen. Arlen Specter of Pennsylvania, the ranking Judiciary Committee Republican, has posed a series of questions to Mr. Mukasey about his suggestion that the president’s authority as commander in chief could supersede laws passed by Congress, an interpretation favored by the Bush administration. And the committee is still waiting for the White House to deliver two secret Justice Department memos reported to uphold waterboarding and other painful tactics as legal and deny that it violates the congressional ban on “cruel, inhuman and degrading treatment.”

Much depends on Mr. Mukasey’s future responses to these persistent questions. He holds in his hands whether the presence of a new attorney general will truly mark an end to the secretive and partisan era of the departed Alberto Gonzales, when the Justice Department drafted secret memos undermined the Constitution and laws of Congress and sought Bush loyalists as federal prosecutors.

A perception is growing that it is not enough to have an attorney general who is merely better than Mr. Gonzales. His successor should clean up the mess in the Justice Department that Mr. Gonzales created and the Bush White House tolerated.

Declaring an end to waterboarding and other torture would be a good start.