Ashcroft became the nominee for U.S. attorney general after losing his reelection bid in November 2000 to another former Missouri governor, Mel Carnahan. Carnahan died in an plane crash weeks before the election, and his wife, Jean, served in his stead.
Ashcroft was thrust into a central role after the Sept. 11 terrorist attacks. He presided over a federal dragnet that apprehended and deported hundreds of Arab and South Asian foreign nationals on immigration violations but resulted in relatively few convictions for terrorism.
Ashcroft Resigns: The attorney general resigned Tuesday, one of the first two members of the Cabinet to quit before the start of a second term.
Transcript: Author Ronald Kessler discusses Bush's second term and recent resignations.
Ashcroft's resignation letter to President Bush, dated Nov. 2 and released Tuesday.
Video: The Post's Dana Milbank
Ashcroft's Legal Record
Ashcroft helped shepherd through Congress a package of stringent anti-terrorism measures, the USA Patriot Act, and used the new powers to dramatically restructure the missions of the FBI and the Justice Department, which became primarily focused on thwarting another attack.
Ashcroft came under persistent assault from Democrats, civil libertarians and even some Republicans, who questioned the Justice Department's use of secretive court proceedings and aggressive surveillance and search techniques. The Supreme Court rebuffed one of the department's central anti-terrorism strategies, ruling in June that men detained indefinitely without charges as enemy combatants by the U.S. military are entitled to lawyers and access to U.S. courts.
Anthony D. Romero, executive director of the American Civil Liberties Union, compared Ashcroft to A. Mitchell Palmer, who oversaw raids targeting thousands of alleged radicals as attorney general in the Woodrow Wilson administration.
"This attorney general has been one of the most divisive forces in the Bush administration," Romero said. "His legacy will show that he was one of the worst attorney generals in American history, with an outright hostility for civil liberties and overt disdain for critics. . . . If President Bush wants to make good on his promise to unite the country, he can do no better than to start with the attorney general."
But leading Republicans argue that Ashcroft helped transform the Justice Department and FBI at a time when the United States is under persistent threat of attack from al Qaeda and other terrorist groups.
"His service came at a challenging time in our history," Senate Majority Leader Bill Frist (R-Tenn.) said in a statement. "His dedication and commitment to fighting the war on terror has been critical to ensuring the safety . . . in our homeland."
A longtime friend of Ashcroft's expressed bitterness that the White House had originally welcomed him as a lightning rod who drew criticism away from Bush, then decided not to stand by him. "He was something to offer to evangelicals," said the friend, who declined to be identified. "They used him, and now they're done with him and he's being tossed aside."
In his letters to Bush and to Justice employees, Ashcroft focused in part on accomplishments other than fighting terrorism. They include, he said, more prosecutions of gun crimes, a crackdown on drug trafficking, and the convictions of executives at Enron, WorldCom and other companies for corporate crimes.
Ashcroft pushed the envelope on many hot-button issues. His department endorsed an expansive interpretation of the Second Amendment right to bear arms and sought to gain access to edited records of abortion patients from the Planned Parenthood Federation of America as it defended the Partial Birth Abortion Ban Act in a lawsuit.
On many issues, Ashcroft's responses to criticism were often confrontational. He told a stunned Senate Judiciary Committee in December 2001 that criticism of government tactics "only aids terrorists," and said two years later that librarians worried about FBI surveillance powers were "hysterics."
This April, Ashcroft, testifying before the Sept. 11 commission, characterized a legal memo written by one of the panel's Democratic members as the "single greatest structural cause for the September 11th problem." The bipartisan commission and many legal experts disputed the claim.
Ashcroft plans to give speeches, join corporate boards and perhaps work with universities, administration officials said.
Research editor Lucy Shackelford contributed to this report.