A federal judge in San Francisco is raising questions about the constitutionality of a law designed to dismiss suits against telecommunications companies accused of cooperating with government wiretapping.

Chief U.S. District Judge Vaughn Walker has asked President Obama's Justice Department to present its views by Wednesday on whether the law gives the attorney general too much power to decide whether a company is immune from lawsuits. Obama supported the measure as a senator when Congress approved it last year.

Department spokesman Charles Miller declined to discuss the administration's response before Wednesday's filing. But Obama's vote for the bill last summer, and statements by Attorney General Eric Holder at his confirmation hearing last month, indicate the department will defend the law.

Walker is presiding over lawsuits in which telecommunications companies' customers have accused the firms of illegally sharing their telephone and e-mail records with federal agents.

Then-President George W. Bush acknowledged in 2005 that he had ordered the National Security Agency to intercept messages between Americans and suspected foreign terrorists without approval from the courts or Congress. His administration refused to discuss telecommunications companies' role in the wiretapping program.

After Walker allowed AT&T customers to proceed with their lawsuit, Bush won congressional approval last year of a law that authorized the surveillance program and sought to shield the companies from legal claims.

Under the law, a judge is required to dismiss a wiretapping suit against a telecommunications firm if the attorney general explains the firm's role to the judge in a confidential statement. The government would say either that the firm had no role or that it participated based on assurances that the president had approved the eavesdropping to protect the nation from terrorism.

Bush's attorney general, Michael Mukasey, filed a statement with Walker seeking dismissal of the AT&T suit. Holder, questioned at his Senate confirmation hearing last month, said he would reaffirm Mukasey's statement and defend the law unless he had "compelling reasons" to do otherwise.

In a Feb. 11 order, Walker said the law appeared to set no criteria for the attorney general to use in deciding whether to seek immunity for a company.

Walker asked the opposing sides in the AT&T case to submit arguments by Wednesday on whether the law violates a 1944 Supreme Court ruling that set constitutional limits on laws granting power to the president.

The point of the 1944 ruling, said the phone customers' lawyer, Cindy Cohn of the Electronic Frontier Foundation, was that "Congress is supposed to write the laws. Congress isn't supposed to abdicate the ability to write those laws to the president."

Printed courtesy of author Bob Egelko and the San Francisco Chronicle and www.sfgate.com