WASHINGTON, March 11 — A leading Senate Democrat demanded on Sunday that Attorney General Alberto R. Gonzales step down, saying he had politicized his office at the expense of the nation’s laws.

The call by Senator Charles E. Schumer, Democrat of New York, came as the Justice Department faced growing criticism over the ouster of eight United States attorneys and the Federal Bureau of Investigation’s use of expanded surveillance powers to improperly obtain personal records of citizens.

In an interview on the CBS News program “Face the Nation,” Mr. Schumer, the Senate’s third-ranking Democrat, said Mr. Gonzales had shown more interest in carrying out President Bush’s agenda than in upholding the law and protecting the rights of citizens.

The senator also said Mr. Gonzales, a former White House counsel who has run the Justice Department since 2005, had been “even more political” than his predecessor, John Ashcroft, who was among the most polarizing members of Mr. Bush’s cabinet in the president’s first term.