The New York Times reports that beginning Tuesday, the attorney general will deliver more than a dozen speeches in states crucial to President Bush's 2004 re-election.
The effort comes as some in Congress, including a few conservatives, are proposing curtailing the Patriot Act.
Not only does Ashcroft want the law sustained, he'd like it strengthened.
The law, which passed Congress in the immediate aftermath of the Sept. 11, 2001 terrorist attacks, allowed law enforcement to conduct more searches without notifying subjects and use surveillance from intelligence investigations — which is approved on a lower standard of evidence — in criminal prosecutions.
It also permitted agents to screen medical, library and other records without probable cause, says the American Civil Liberties Union, and prohibited doctors or librarians from telling someone their records had been searched.
The ACLU is suing to block part of the Patriot Act. Some 150 communities have adopted resolutions opposing it, and a Republican Congressman recently introduced a bill to strip one section of the law.
However, the Justice Department believes most Americans don't harbor suspicions.
"The majority of American people are clearly supportive of our counterterrorism efforts, including the use of the Patriot Act," Mark Corallo, a department spokesman, told The Times.
"It's important that after months of misinformation being spread by a small but vocal minority inside the Beltway that we go out beyond Washington and talk to people in law enforcement and let them know that their efforts are appreciated," he said.
In May, the Justice Department released statistics to show that it has used some Patriot Act powers relatively infrequently. It had detained fewer than 50 people as material witnesses without charging them in the war in terror as of January and had visited fewer than 10 mosques.
Public libraries have been contacted about 50 times by federal investigators as part of their anti-terrorism efforts, but the Justice Department won't say whether they looked through or took information from their records.
Ashcroft might seem an odd choice to mount a public pitch for the law.
No member of the Mr. Bush's Cabinet faced a tougher nomination fight that Ashcroft, a staunch conservative. And his department has been at the center of several battles over civil liberties in the war on terrorism, from the detention of 700 immigrants after Sept. 11, to the question of whether Zacarias Moussauoi has the right to question al Qaeda suspects in U.S. custody as he fights to escape the death penalty.
But a Republican consultant told The Times: "The administration realizes that Ashcroft is a bit of a lightning rod. He has his down sides, but not in the realm of prosecuting terrorism and protecting national security. He works well in that area."
At a Congressional hearing in June, Ashcroft said, "Our ability to prevent another catastrophic attack on American soil would be more difficult if not impossible without the (USA) Patriot Act."
But he added, "the law has several weaknesses which terrorists could exploit, undermining our defenses."
Ashcroft said he wants the Patriot Act changed so that anyone supporting or working with suspected terrorist groups can be prosecuted as "material supporters;" all terrorist acts can result in the death penalty or, at least, life in prison; and suspected terrorists can be held indefinitely before trial.
The ACLU takes issue even with Ashcroft's speaking campaign. The group says the schedule is being kept secret to discourage protest.
In a statement, ACLU legislative director Laura W. Murphy said the trip "raises two serious questions: is this tour — which incidentally hits Iowa, Michigan and Ohio – political in nature and how prudent is it to be spending public money on a 'PATRIOT Act' charm offensive?"