Fred Thompson says the country faces different challenges now than it did when he spurned overtures to run for president in 2000, leading him to consider a return to politics.

"I think that everybody was kind of sitting back, taking it easy and thinking that, you know, peace and prosperity were going to kind of last forever. I think we know better than that now," the former Tennessee senator told The Associated Press.

"We live in a more dangerous [time of] things that threaten our very existence, things that threaten our peace, things that threaten our economic stability."

In an interview Saturday night before speaking to the Virginia GOP, Thompson would not talk in detail about why he believes he might make a good president and he struggled to name his greatest accomplishment in the Senate.

During his 1994-2002 Senate tenure, he was considered a reliably conservative vote. But he had few significant legislative achievements and he established a reputation as a less-than-hard worker.

"That's one rap that you can cure," Thompson said.

Defending his record, he said he managed the homeland security bill in the full Senate and added: "There were a lot of things. ... It doesn't always have to do with putting your name on a piece of legislation. There was an awful lot of bad legislation that I helped to stop for one thing."

But, he said with a smile, "We'll have a chance to get into all that when I start telling everybody what a wonderful person I am. But we're not quite at that stage."

At least not yet.

After flirting with a candidacy for months, the former senator and actor known to millions as the tough prosecutor on NBC's "Law & Order" took the first formal step toward the race for the GOP nomination Friday in establishing a preliminary campaign committee.

Thompson, however, said he still was not ready to commit to a 2008 campaign.

"We've not made a final decision on it. But obviously we're thinking pretty seriously about it," he said. "Everybody who has an opportunity to make even a small difference in the course of the direction of the country has got to look at that very seriously."

Among his considerations, he said, was making sure "the man fits the times."

Despite his coyness, Thompson is all but certain to join the crowded GOP field led by Rudy Giuliani, John McCain (news, bio, voting record) and Mitt Romney. Thompson's entrance could come as early as July.

Fundraising was expected to begin in earnest Monday. Headquarters are planned for Nashville, Tenn., and the Washington, D.C., area. A campaign team is forming. Tentative visits to Iowa, New Hampshire and other early primary states are in the works.

A Washington Post poll published Sunday found that Giuliani remained the front-runner, but suggested his popularity could be showing signs of stalling because of his support for abortion rights and gay rights. Thompson's candidacy could quickly turn the contest into a four-way battle, according to the poll.

Thompson, 64, said much has changed since he rejected calls to run for president in 2000. Encouraged by an effort to draft him into the 2008 race, Thompson said he now finds the prospect appealing for several reasons.

"I am married now, have two children at home. I spend a lot of time thinking about the kind of world that they're going to grow up in, spend a lot of time talking to my wife about that," he said. "And I think the country's different. I think we have challenges now that we didn't have in 2000."

He said that in the years since he left public office and focused on his acting career, he has maintained his interest in what is going on in the world.

"It's ultimately up to the American people what they think about me," Thompson said. "I've never desired to hold the office, particularly. In fact, not at all. But, at this stage of things, I sometimes think that I do desire the opportunity to do some things that only a president can do."

He said his ambivalence until now about the presidency ultimately might make him a better leader and, thus, a better fit for the White House than others.

"If a person craves power for the sake of power, if he craves the office for the sake of holding the office, he's got his priorities mixed up," Thompson said. "It's a desire to do something not to be something."

The Southerner with Hollywood star power and mostly conservative Senate credentials fares well in national popularity polls. But he would enter the race some six months after the top-tier trio. He trails them significantly in money and organization, raising questions about whether he can turn buzz on the Internet and in Washington into actual votes when the primaries begin in less than eight months.

Undaunted, he belittled the notion that candidates can only be competitive if they have had a campaign organization in place for months and if they raise upward of $100 million this year.

"I don't know who made those rules. I don't know who the experts are. I'm too late to follow those rules even if I wanted to, and I don't want to," Thompson said. "At the end of the day, the people have to be receptive to you and your message. It doesn't matter how many campaign advisers you've got or how much money you can spend. If it's meant to be, it'll be."