A U.S. Senate panel Tuesday held a hearing on President Bush's use of a constitutional tool to ignore laws passed by Congress. The Bush administration defended the practice.

At issue are so-called signing statements, which President Bush has attached to laws he has signed to express his opposition to provisions in the laws.

A study by the Boston Globe newspaper says President Bush has signed some 750 such memos challenging laws passed by Congress - including a ban on the torture of U.S.-held prisoners and provisions in the anti-terrorism law known as the Patriot Act that call for increased congressional oversight. The administration disputes that number, saying 110 such statements have been issued.

Arlen Specter

Nevertheless, the Republican chairman of the Senate Judiciary Committee, Senator Arlen Specter of Pennsylvania, expressed concern about the practice.

"It is a matter of separation of power," said Arlen Specter.

Democrats said the signing statements are an example of the administration's expansion of executive power:

Senator Dianne Feinstein is a California Democrat:

"I believe this new use of signing statements is a means to undermine and weaken the law, and that is should be a serious concern to all Americans," said Dianne Feinstein.

Michelle Boardman, deputy assistant attorney general at the Justice Department, defended the legality of the signing statements, and said they are nothing new:

"Every president since Eisenhower has used Constitutional signing statements," she said.

At the White House, spokesman Tony Snow also defended President Bush's use of such statements.

"He has tried to preserve, protect and defend the Constitution as he is bound by the Constitution, but he also is enjoined by the Constitution dutifully to carry out the laws and to execute the laws of the United States," said Tony Snow. "What the signing statements are designed to do is to make sure both of those duties are kept in balance."

The Senate Judiciary Committee will have an opportunity to question Attorney General Alberto Gonzales about the issue when he appears before the panel next month.