Lindh's attorney, James Brosnahan, who negotiated the sentence in a plea bargain in 2002, said it was the best deal he could get at the time. But he said the sentence should be reconsidered after the government agreed to release another U.S.-born Taliban fighter, Yaser Esam Hamdi, from detention without charges.
Ashcroft rejected the idea, saying Lindh received all the safeguards of the judicial process and the outcome was fair.
"Lindh was fully adjudicated and had his opportunity in court to state his position, and the system operated to provide a punishment for his activities which were clear and unmistakable," Ashcroft told reporters in the Netherlands.
"It's not really helpful to compare one case to another case. In each case the system operates. Justice was done in his case, and I believe we try to be consistent and effective in providing justice," he said.
Ashcroft was in The Hague to discuss tightening security cooperation with the Dutch government and to meet with European Union justice and interior ministers convening for a two-day conference.
Brosnahan made the request Monday. Speaking in San Francisco, he argued that Lindh had fought alongside the Taliban in a civil war against the Northern Alliance, that he is not a terrorist and that he never fought against U.S. troops.
Hamdi, who had been held for three years without trial, will be required to relinquish his U.S. citizenship and will be sent to Saudi Arabia, where he grew up.
"Comparable conduct should be treated in comparable ways in terms of sentencing," Brosnahan told reporters.
Only U.S. President George W. Bush can commute Lindh's sentence.
Lindh, 23, pleaded guilty in a civilian court to supplying services to the Taliban government and carrying explosives for them. He and Hamdi were both captured in late 2001.