The Justice Department said yesterday that it would not object to the withdrawal of an appellate court decision that affirmed the president's power to detain Jose Padilla as an enemy combatant, a decision the Bush administration hailed as vital in the fight against terrorism.

The U.S. Court of Appeals for the 4th Circuit indicated last week that it might vacate the ruling because the government's version of why Padilla is a threat has changed. Officials initially accused Padilla, a U.S. citizen who was imprisoned by the military without charges or a trial for more than three years, of plotting to detonate a radiological "dirty bomb" and conspiring to blow up apartment buildings in the United States.

But a federal grand jury recently indicted Padilla on terrorism charges that did not mention the bombing plots. The 4th Circuit in Richmond declined last week to authorize Padilla's transfer from military to Justice Department custody and asked prosecutors to explain why it should not vacate the ruling issued in September because it was based on "different facts.''

In their response yesterday, prosecutors said to go ahead. The court would be "well within its discretion" to withdraw the earlier ruling, they said in a filing with the 4th Circuit, because Padilla's challenge to his military detention is moot in light of the charge in the criminal justice system. At a minimum, they said, the court should authorize Padilla's transfer out of military custody.

Legal experts said the government is willing to sacrifice the 4th Circuit decision -- which allowed the president to detain indefinitely a U.S. citizen captured on U.S. soil without criminal charges -- because it fears the U.S. Supreme Court might overturn it. That would deal a major blow to the Bush administration's strategy for detaining terrorism suspects.

The high court is considering whether to hear Padilla's appeal of the 4th Circuit decision, an appeal the Justice Department yesterday argued is also moot.

"I think this is part of a strategy to make this case as difficult as possible to get to the Supreme Court,'' said Michael Greenberger, a former Justice Department official who heads the Center for Health and Homeland Security at the University of Maryland.

Padilla, a former gang member, was arrested in Chicago in 2002 and declared a combatant by President Bush a month later. Padilla has been held in a U.S. naval brig ever since, and his case has come to symbolize a broad legal struggle over governmental powers to fight terrorism since the Sept. 11, 2001, attacks.

Padilla is one of two U.S. citizens held as enemy combatants since the terrorist attacks on the World Trade Center and Pentagon. In its September ruling, the 4th Circuit panel accepted the government's argument that Bush had the authority to detain Padilla and that such power is essential to preventing terrorist strikes.

Attorneys for Padilla have until Friday to file their briefs on whether the 4th Circuit should vacate the earlier ruling. Defense attorneys declined to comment yesterday.

Jose Padilla has been in federal custody since 2002. Until recently, he was held without charge.