Attorneys for John Walker Lindh, the suburban Californian convicted of fighting for the Taliban in Afghanistan, asked President Bush yesterday to commute Lindh's 20-year prison sentence.

The lawyers cited what they called disparities in the treatment of Lindh and Yaser Esam Hamdi, a U.S. citizen who the government says also fought for the Taliban after the Sept. 11, 2001, terrorist attacks. While Lindh pleaded guilty and is serving his sentence at a California prison, the government last week agreed to release Hamdi from custody and fly him home to Saudi Arabia.

"Mr. Hamdi was comparable in many ways to John Walker Lindh, and that's what causes us to believe it is basically unfair to have Lindh serve the remainder of his sentence," James J. Brosnahan, an attorney for Lindh, said at a news conference yesterday in San Francisco. "People need to understand that Lindh is an American, he has family here and he never fought against America."

Lindh's mother, Marilyn Walker, added: "I hope America can find it in her heart to forgive John."

Legal experts said it is highly unlikely that Bush, who has made the war on terrorism the centerpiece of his reelection campaign, would agree to reduce Lindh's sentence. Under the Constitution, only the president can issue pardons or commutations.

"Not a chance," said Chris Schroeder, who ran the White House Office of Legal Counsel for two years during the Clinton administration. "Putting aside the perhaps crass political reasons," Schroeder said, "Lindh's prosecution was so recent that folks who made the decisions to go ahead and eventually settle the case are still part of the Department of Justice, and they will make their views known."

Federal prosecutors in Alexandria would not comment on Lindh's commutation petition, which was filed yesterday and does not specify how many years Lindh wants taken off his sentence. Claire Buchan, a White House spokeswoman, would say only that all clemency petitions are reviewed by the Justice Department, which makes recommendations to the president.

The debate refocused attention on a case that aroused passions across the country. Lindh converted to Islam as a teenager in Marin County, Calif., and studied Arabic in Yemen and Pakistan before venturing to Afghanistan. Prosecutors say he fought for the Taliban before and after Sept. 11 until his unit surrendered to Northern Alliance forces in November 2001.

Lindh initially faced charges that could have sent him to prison for life, including conspiring to kill Americans abroad. He pleaded guilty in July 2002 in U.S. District Court in Alexandria to one count of providing services to the Taliban and one count of carrying explosives during a felony.

At his sentencing, Lindh, then 21, tearfully apologized and said he never supported terrorism or fought against Americans. Yesterday, his attorney recalled the emotion surrounding Lindh's case, which he said was especially heated because it was prosecuted in Northern Virginia, near the Pentagon, and so close to Sept. 11.

"There comes a time after the heat of war when people begin to look more fairly at a situation," said Brosnahan, who called on Bush to show "compassion" for Lindh.

According to Justice Department statistics, commutations are rarely granted. President George H.W. Bush granted three of 735 petitions, and President Bill Clinton granted 61 of 5,488 petitions. Government officials could not provide statistics on President Bush, but Lindh's attorneys said he has granted only two commutations, both in drug cases.

Lindh's attorneys emphasize the similarities between Lindh and Hamdi, whose flight home to Saudi Arabia is expected any day. The U.S. military captured Hamdi with pro-Taliban forces in Afghanistan in 2001 and held him in solitary confinement for nearly three years after declaring him an enemy combatant. Hamdi did not face criminal charges.

"I hope America can find it in her heart to forgive John," said Marilyn Walker, with Frank Lindh. They are John Walker Lindh's parents.JOHN WALKER LINDH