After months of flirting with the idea of a White House run, former Sen. Fred Thompson, a Republican from Tennessee, formally declared his candidacy Thursday.
He is selling himself as the only genuine conservative among the Republican front-runners. But the question for the politician-turned-actor-turned-politician is -- can he successfully play that role?
The former star of NBC's "Law & Order" and co-star of "Die Hard 2" began auditioning for the role of the ultimate leading man with an appearance on "The Tonight Show With Jay Leno" Wednesday, a Web video Thursday morning and an official campaign speech in Des Moines, Iowa, Thursday afternoon.
"I am determined that we make the decisions that leave us a stronger nation, a more prosperous nation, and a more united nation, and that's why I'm running for the presidency of the United States," Thompson said to applause.
The former actor spoke after a short campaign video called "The Hunt for Red November," a nod to his work on the 1990 movie "The Hunt for Red October."
He depicted himself as a conservative alternative to former Republican Gov. Mitt Romney of Massachusetts, former New York Mayor Rudy Giuliani and Sen. John McCain, R-Ariz., candidates with whom many conservatives are dissatisfied. Thompson hopes to take advantage of that.
"I still have the same common sense conservative beliefs that I did when I ran in 1994," Thompson said, referring to his successful bid for the Tennessee Senate seat vacated by then Vice President Al Gore.
But the former senator, who has also served as a lawyer and lobbyist, is not universally beloved by the Republican right.
"There's a fair amount of rhetoric there, but in terms of action and results we just don't see it. ... It's almost like he's gotten another Hollywood role where he's supposed to play a conservative," said Richard Viguerie, chairman of conservativehq.com.
Thompson's Senate record is generally conservative, but not reliably so -- and he seemed to pride himself on that.
A 1996 memo titled Breaking from the Republican Pack, obtained from Thompson's Senate archives, trumpets examples of his "legislative independence from 'the party line'" when he "voted against the Republican majority."
The memo listed Thompson's more liberal positions on campaign finance reform, consumer protections and tort reform. The memo was prepared, a Thompson source said, after Democrats in Tennessee accused him of being too partisan.
But these days, Thompson sells himself as a reliable Republican, though he was teased by his Republican rivals of being lazy at Wednesday night's Republican debate in New Hampshire.
"Maybe we're up past his bed time," McCain said during the televised debate when asked about Thompson, who did not attend.
Other GOP rivals took shots at Thompson's credentials.
"I think he's done a pretty good job of playing my part on 'Law & Order,'" Giuliani said.
Whatever Thompson's weaknesses, influential conservatives say the '08 election may be his to lose.
"I think a lot of conservatives, they've been sitting by the phone waiting for Sen. Thompson to call and they're ready to go on a date and see if it works out," said Richard Land of the Southern Baptist Convention. Land said the race is Thompson's to lose.