WASHINGTON (CNN) -- Fred Thompson is banking on the idea that it's better to be late than to be one of the other guys.
Fred Thompson will join the race for the GOP nomination only four months before the first voting.
"For [Rudy] Giuliani, of course, it is the social issues," GOP activist Cyndi Mosteller said. "For John McCain, it's become the immigration issue. For Mitt Romney, there is this sense of what is his core? Is he John Kerry Republican in terms of his flip-flopping?"
Mosteller is a veteran Republican activist in Charleston, South Carolina. A McCain backer until a few months ago, she is now helping Thompson try to prove waiting so long to officially jump in wasn't a mistake.
"I think that Fred Thompson is the intersection of conservative ideology and political electability," she added.
Political observers say Thompson may be late entering the race. The first voting is only four months away and the others have been in Iowa, New Hampshire, South Carolina and beyond for months.
Thompson plans to announce that he's jumping into the presidential race at 12:01 a.m. Thursday on his Web site, 90 minutes after his rivals debate in New Hampshire. Although he isn't participating in the debate, he is airing his first campaign ad at the same time on Fox News.
"Expectations are sky high, which means he better perform flawlessly out of the box or a lot of people are going to start grumbling that he's not the great savior we thought he was," Republican pollster Whit Ayres said.
Thompson is angling for a conservative base that hasn't coalesced around one candidate. He's promising his commitment to outlaw abortion is more than lip service during his speeches this summer.
"I don't think as the president you can do anything halfway," Thompson told CNN in August.
On Iraq, he's in no rush to talk about bringing troops home.
"Right now we need to make every effort to make sure that we don't get run out of there with our tails between our legs," Thompson said.
Thompson is a former federal prosecutor. He made his mark as Republican counsel on the Senate Watergate committee and served eight years in the Senate from Tennessee.
But bring up his name, and one word trumps all others.
"Actor. He is known as an actor," Ayres said. "Senator Thompson is not that well known. In many ways it is a vessel into whom many Republicans have poured their hopes and dreams. We will see whether those hopes and dreams get realized." E-mail to a friend
All About Fred Thompson (Politician)