A Bush administration lawyer resisted a San Francisco federal judge's attempts Wednesday to get him to say whether Congress can limit the president's wiretap authority in terrorism and espionage cases, calling the question simplistic. You can't possibly make that judgment on the public record" without knowing the still-secret details of the electronic surveillance program that President Bush approved in 2001, Justice Department attorney Anthony Coppolino said at a crucial hearing in a wiretapping lawsuit. Chief U.S. District Judge Vaughn Walker didn't rule immediately on the government's request to dismiss the suit by an Islamic charity in Oregon, which says a document that federal authorities accidentally released showed it was wiretapped. But Walker, in an extensive exchange with Coppolino, said Congress had spoken clearly in a 1978 law that required the government to obtain a warrant from a secret court before it could conduct electronic surveillance of suspected foreign terrorists or spies. "The president is obliged to follow what Congress has mandated," Walker said. The case may determine whether any U.S. court can judge the legality of Bush's covert order to the National Security Agency to intercept phone calls and e-mails between Americans and suspected foreign terrorists without seeking judicial approval. After Bush acknowledged the existence of the program, Congress temporarily extended it in August and now is debating whether to protect telecommunications companies from lawsuits for their past cooperation. Most lawsuits challenging the program have been dismissed because the plaintiffs were unable to show that they had been wiretapped.