Attorney General John Ashcroft on Friday defended the FBI's reorganization plan against charges the new, proactive approach to fighting terror will infringe on Americans' constitutional rights. 

"If you sit and wait for a crime to happen, and then you respond to it, that isn't a very good prevention strategy," Ashcroft said in an interview with Fox News. "You have to be able to develop or to get a lead from your own information, not wait for something to happen to trigger your activity." 

Ashcroft has been criticized by civil libertarians who fear the FBI's new approach to fighting crime will infringe on a range of personal liberties. 

Opposition to the plan to shift key parts of the agency from law enforcement to domestic intelligence came almost immediately after Ashcroft announced a draft outline Thursday that frees the bureau to conduct investigations without prior approval from headquarters. 

The new guidelines also allow agents to enter public areas such as churches, libraries and meetings of political organizations, from which they were previously barred. Ashcroft maintained these new guidelines actually further enable the U.S. government to protect constitutional guarantees. 

"I want to protect the constitutional right of individuals. I want to protect the right of Americans to life, liberty and the pursuit of happiness," he said in the interview. "Protecting against terrorism protects the most important of our rights." 

FBI agents will be encouraged to participate in undercover investigations by "visiting places and events which are open to the public, on the same terms and conditions as members of the public generally, for the purpose of detecting or preventing terrorist activities," according to the "Attorney General's Guidelines on General Crimes, Racketeering Enterprise and Terrorism Enterprise Investigations." 

"Our philosophy today is not to wait and sift through the rubble following a terrorist attack," Ashcroft told a news conference Thursday. 

Critics lined up to denounce the new guidelines as another erosion by the Bush administration of Americans' constitutional freedoms in the name of fighting terrorism. 

"The administration's continued defiance of constitutional safeguards seems to have no end in sight," complained Michigan Rep. John Conyers, the top Democrat on the House Judiciary Committee. 

"It only serves the purpose of heightening the scare in the society and the paranoia against Muslims," said Shaker Elsayed, secretary general of the Muslim American Society. 

The new outlook stems from recent criticism from Congress and others the FBI failed to string together a pattern of suspicious activity that was occurring in the United States prior to Sept. 11. 

Though Mueller says none of the information provided by Phoenix and Minneapolis field agents about Arabic men training at flight schools could have helped them predict the day of terror, agents were hindered from continuing investigations that may have turned up useful leads. 

With the combined change in structure, mission and techniques employed at the bureau, Mueller and Ashcroft hope agents will be able to take on new initiatives that they were previously prohibited from doing under restrictions laid down in the 1970s, including conducting computer and Internet searches that weren't even an investigative tool back then. 

"To give the FBI the right to go to public places on the same terms and conditions as the public, to give agents the right to search the Internet, to go where any 12- or 14-year-old who knows how to operate a computer can go," Ashcroft said Friday, "these are things the FBI needs the authority to do." 

"Nothing that we have put in the revised provisions or guidelines can, should or would erode the constitutional guarantees or even any statutory guarantees," he added. 

Ashcroft said nothing in the guidelines would permit the FBI to routinely build files on people or organizations. 

Critics disputed that, arguing a domestic intelligence organization allows the FBI to spy on citizens. 

"They are using the terrorism crisis as a cover for a wide range of changes, some of which have nothing to do with terrorism," said James X. Dempsey, deputy director of the Center for Democracy and Technology. 

Dempsey predicted that one new tool, the power to mine commercial data, will be used in drug and child pornography and stock fraud and gambling and "every other type of investigation the FBI does." 

Stringent guidelines on FBI activities were put in place in the 1970s because of the FBI's domestic surveillance of prominent Americans, including the Rev. Martin Luther King Jr., whose private life was subjected to electronic surveillance. 

The American Civil Liberties Union said the lifting of restrictions could renew abuses of the past. 

King's "persecution by law enforcement is a necessary reminder of the potential abuse when a government with too long a leash seeks to silence voices of dissent," ACLU legislative counsel Marvin Johnson said. 

Others said the authority granted by the new anti-terrorism law passed by Congress in the month following the terror attacks gave the FBI far more leeway than the guidelines would suggest. 

"The impact is far less significant and far less subject to abuse than what was enacted into law" by Congress after the Sept. 11 attacks, said attorney Raymond J. Gustini, who chairs a subcommittee of the American Bar Association on electronic privacy and co-chairs an ABA task force on financial privacy. 

"The FBI really needs this right now. They're under a microscope now more than any other player other than the president. It's very important for the FBI to deliver." 

Fox News' Carl Cameron and the Associated Press contributed to this report.