DES MOINES, Iowa – Fred Thompson, veteran actor and former Republican senator, launched his bid for the presidency Hollywood style. “I’m running for president of the United States,” Thompson told Jay Leno in a taped appearance on NBC’s “Tonight Show” airing Wednesday night. Thompson called top opponents Rudy Giuliani and Mitt Romney formidable but added: “I think I will be, too.” He rejected the notion that he was getting into the race too late, only four months before voting begins. “I don’t think people are going to say, `You know, that guy would make a very good president but he just didn’t get in soon enough,”‘ Thompson said as the studio audience laughed. Poking at his rivals who have been running since the year began, he added: “If you can’t get your message out in a few months, you’re probably not ever going to get it out.” They have not yet settled on a candidate and are searching for someone with like-minded credentials who can win in a general election. Thompson is perhaps best known to millions of Americans as the gruff district attorney Arthur Branch on NBC’s crime drama “Law & Order,” as well as for his roles in more than a dozen movies. During his 1994-2002 Senate tenure, he was considered a reliably conservative vote. He strayed from the party line on a few issues, including advocating for campaign-finance reform. He also was John McCain’s campaign co-chairman in 2000 instead of backing establishment candidate George W. Bush. Thompson spent many years in Washington as a lawyer and lobbyist. He has faced repeated questions about his lobbying work for a family-planning group that sought to relax an abortion rule and for former leftist Haitian leader Jean Bertrand-Aristide. Late-night talk shows have become a popular place for politicians to announce they are candidates for public office. Earlier this year, McCain announced his presidential bid on CBS’ “Late Show With David Letterman.” Arnold Schwarzenegger disclosed to Leno his plans to run for California governor. 160Want local news?Sign up for the Localist and stay informed Something went wrong. Please try again.subscribeCongratulations! You’re all set! In a multiphased campaign rollout, Thompson also called attention to his candidacy with a 30-second ad broadcast during a Republican debate in New Hampshire that he skipped. He will explain the rationale for his candidacy during a 15-minute Webcast on his campaign Internet site just after midnight. Thompson, 65, enters a crowded GOP field and an extraordinarily fluid race. While Giuliani leads in national polls, Romney maintains an edge in the early voting states of Iowa and New Hampshire. Overall, Republican voters have expressed less satisfaction with their choices than Democrats, and Thompson sees that as an opening for his candidacy. It won’t be easy for the former Tennessee senator. His campaign has been beset by lackluster fundraising and multiple staff changes, the most recent coming Tuesday with the departure of his spokesman of just two weeks, Jim Mills. Thompson starts some eight months after his eight rivals began campaigning, and he lags behind Giuliani and Romney in both money and organization. In June, Thompson fell short of his $5 million fundraising goal by $1.5 million. Still, Thompson consistently ranks among the top Republicans in national polls and state surveys. A Southerner with a mostly right-leaning Senate record and a plainspoken style, he is looking to capitalize on discontent with the current choices among conservatives who make up a significant segment of GOP primary voters.