"There's nothing specifically new in what Thompson did," said Michael X. Delli Carpini, dean of the Annenberg School for Communication at the University of Pennsylvania, noting that Arnold Schwarzenegger announced his California gubernatorial candidacy on Leno's show in 2003 and Sen. Hillary Rodham Clinton (D., N.Y.) launched her presidential campaign on the Web this year.
"But Thompson certainly combined all of those elements in a new way," Delli Carpini said.
Whether the candidate's use of the tools of political communication - or his decision to skip a Wednesday night debate in New Hampshire - matters in the long run remains to be seen.
His tactics did get him sustained news coverage and considerable control over its content. Even the most-used clips from the debate were the ones about Thompson, his absence being the subject of the opening question.
Of more significance, analysts say, is whether Thompson - second among GOP candidates in most polls, behind former New York Mayor Rudy Giuliani - can distinguish himself from other leading candidates in the coming weeks and establish himself as the top choice of conservative leaders.
In his Web-site speech, which talked about the fight against Islamic terrorists but did not mention the war in Iraq, he recounted his life story and portrayed himself as a man of "sound, conservative First Principles."
The lawyer/actor/lawmaker called for reducing federal involvement in public education, lowering taxes, appointing judges who interpret the Constitution rather than rewrite it, protecting the sanctity of human life, and making health insurance a market-based commodity not linked to employment.
His overall theme, delivered in a serious, measured baritone, was the need to limit the federal government.
"A government that's big enough to do everything for us is powerful enough to do anything to us," he said at one point, adding later: "I don't accept it as a fact of life beyond our power to change that the federal government must go on expanding more, taxing more, spending more, forever."
If the rhetoric had a Reaganesque ring to it, that was no accident.
"His people want him to be seen as the next Ronald Reagan, but the analogy has some problems," said Dennis Goldford, professor of politics at Drake University in Des Moines. "Right now, the name 'Thompson' stands for 'none of the above.' He's not offering a new or different message so much as a new and different messenger."
Questions remain about Thompson's staying power as a candidate. The early Thompson story line has been one of laziness and disorganization. His efforts in the coming weeks will either erase or confirm that.
His exploratory effort, launched June 1, has been plagued by staff turnover and lackluster fund-raising.
At the very least, analysts say, his relatively late entry constrains his ability to build political organizations in the early states, where many top operatives and volunteers have signed on with others.
"As a social conservative, Thompson doesn't have a big natural constituency in New Hampshire," said Andrew Smith, director of the Survey Center at the University of New Hampshire. "So he doesn't have a huge margin of error here."
But the Republican race remains fluid four months before the voting starts. And if Thompson can be an effective candidate quickly, he'll be able to point to what he told Leno on Wednesday night:
"I don't think people are going to say, 'That guy'd make a very good president, but he didn't get in soon enough.' "
Contact senior writer Larry Eichel at 215-854-2415 or firstname.lastname@example.org.