WASHINGTON – President Bush nominated yesterday one of his closest advisers, Alberto Gonzales, to replace John Ashcroft as attorney general.

Mr. Gonzales, who is 49, would be the first Hispanic to serve as the highest law enforcement official in the country. He is expected to have little trouble winning confirmation in the Senate, although leading Democrats have pledged to grill him about a 2002 memo in which he argued that America’s armed forces were not bound by international law in their treatment of Al Qaeda detainees.

While Democrats appear to lack both the muscle and the inclination to reject the Gonzales nomination, his appearance before the Senate will probably reignite a debate over the USA Patriot Act, which is due to expire next year.

Mr. Bush praised his choice for attorney general yesterday, emphasizing Mr. Gonzales’s humble upbringing in Texas. He also singled out Mr. Gonzales, who is White House counsel, for his advice regarding the war on terrorism. “His sharp intellect and sound judgment have helped shape our policies in the war on terror – policies designed to protect the security of all Americans, while protecting the rights of all Americans,” the president said.

Mr. Gonzales, who often works behind the scenes, burst onto front pages this summer when his memo of January 25, 2002, regarding the war on terror was disclosed. That memo said in part that the new war “renders obsolete Geneva’s strict limitations on questioning of enemy prisoners and renders quaint some of its provisions.” The reference was to the Geneva Convention relative to the treatment of prisoners of war.

A memo of August 1 of the same year concluded that federal prohibitions on torture do not apply to those Al Qaeda detainees held at the American military prison in Guantanamo Bay, Cuba.

Mr. Gonzales also played a key role in drafting the rules for military courts for those prisoners whose detentions have recently been found unconstitutional by the Supreme Court.

The senior Democrat on the Senate Judiciary Committee, Patrick Leahy of Vermont, vowed yesterday to make an issue of those memos. “These confirmation hearings will be a rare opportunity for the Senate and the public to finally get some answers on several issues for which the administration has resisted accountability, including its use of the Patriot Act, the lack of cooperation with Congress on oversight, and the policies that have been rejected by the courts on the treatment of detainees,” Mr. Leahy said. “This also may be the only remaining forum in which to examine more fully the steps that were taken to weaken U.S. policy on torture in the period that led to the prison scandals at Abu Ghraib and Afghanistan.”

Other Democrats, however, spoke positively of the president’s choice to replace one of the members of the first Bush Cabinet most hated by the minority party.

“It’s encouraging that the president has chosen someone less polarizing. We will have to review his record very carefully, but I can tell you already he’s a better candidate than John Ashcroft,” said Senator Schumer, a Democrat of New York, according to the Reuters news service.

For social conservatives concerned about Mr. Gonzales’s relatively neutral record on abortion, his nomination is privately being met with great relief. “This means that Alberto will not be nominated for the Supreme Court,” a lobbyist on the issues said yesterday. The White House is said to be vetting nominees currently to replace Chief Justice Rehnquist, who is ill with cancer of the thyroid.

“Alberto Gonzales wrote the first Patriot Act,” a former speechwriter for President Bush, David Frum, said in an interview. “He will make an ideal attorney general to take responsibility for writing the Patriot Act when it expires in 2005.”

Senator Cornyn, a Republican of Texas on the Judiciary Committee, told CNN yesterday that Mr. Gonzales was “extremely professional.”

“He doesn’t throw curveballs,” the nominee’s home-state senator said, “and he’ll withstand the confirmation process very well.”

Speaking to reporters yesterday at the Rose Garden, Mr. Gonzales thanked the president and out-going Attorney General Ashcroft. “As a former judge, I know well that some government positions require a special level of trust and integrity,” the nominee said. “The American people expect and deserve a Department of Justice guided by the rule of law, and there should be no question regarding the department’s commitment to justice for every American. On this principle, there can be no compromise.”

The president’s nominee for attorney general has been one of Mr. Bush’s closest allies in his political career. An Air Force veteran and a graduate of Rice University and Harvard Law School, Mr. Gonzales was brought to Austin by then-Governor Bush to serve as a senior counsel. Mr. Bush appointed him Texas secretary of state in 1997 and named him to the Texas Supreme Court in 1999. While serving on the court, he voted to preserve the right of a minor to have an abortion without parental notification if she could prove that the notification would not be in her best interest.

Mr. Gonzales is the first nomination for Mr. Bush’s second administration, which is expected to include considerable reshuffling of the Cabinet. On Tuesday, both Mr. Ashcroft and Commerce Secretary Evans resigned. Also expected to be leaving shortly is Secretary of State Powell, whom the president praised yesterday during a photo opportunity. Two State Department sources told the Sun last week that Mr. Powell has already signaled, to senior staff at Foggy Bottom, his intention to leave in January.