The actor-turned-politician-turned-actor-turned possible presidential candidate sat down with commercial radio hosts for brief interviews, ate a foot-long hot dog and did what any politician does at the State Fair -- campaign.
Thompson spent about two hours at the fair. He seemed delighted to make small talk and pose for pictures with the 100 or so people who crowded around the GOP booth.
"I understand that I've been doing pretty good here without ever coming to the state," he said. "I've been a little bit afraid to come in and mess it up, to tell you the truth."
Many of the people who came to see Thompson in person seemed delighted just to be in the presence of the star of TV's Law and Order program.
Others, like Bridget Sutton of Inver Grove Heights, want Thompson's star power -- and resume -- on the GOP ticket. Sutton says Thompson could draw significant support from middle-of-the-road voters as well as conservatives who are disaffected with the current crop of GOP presidential candidates.
"All of them have their strengths and all of them have their flaws, but from where I stand a lot of it is all show and no go," she said. "It's not that they haven't accomplished things in their own right, but I really think Thompson has a fresh energy and connection with regular Americans."
Thompson told Sutton that he would announce his candidacy within a couple of weeks.
Thompson said all of the Republican candidates are qualified and can beat whoever wins the Democratic nomination in 2008. But he also said he wouldn't be thinking about running if he didn't have something different to offer. In particular, he said he's concerned about the national debt and the global war on terror.
Thompson is not an "official candidate" for president even though he looked like one at the State Fair. He's technically "testing the waters" for a possible presidential run.
Thompson wouldn't tell reporters when he would make his official announcement but he didn't hide his intentions either.
"I'm going to do things at my own pace and my own rate and my own way. So far it doesn't seem to hurt me much," he said. "I'm looking forward to making a statement. I don't think it's any big secret which way I'm leaning right now."
Thompson's statement is a concern to Democrats. The Democratic National Committee alleges Thompson is violating the spirit and intention of federal election law, because he's doing more than simply testing the waters.
They say Thompson is amassing a war chest and political staff that will help him when he is a candidate.
In June, his first month of fundraising, Thompson raised about $3.5 million.
A liberal blogger has filed a complaint with the Federal Election Commission, complaining that Thompson is a full-fledged candidate. DNC spokeswoman Amaya Smith says Thompson should follow the rules that other candidates are following.
"He's been fundraising pretty profusely, which is what he's been doing in Minnesota as well. Through this 'testing the waters' designation, he's been able to not have to file like regular candidates have to file with the FEC and disclose his donors, so he's been getting around that law," she said.
Thompson's campaign says it is operating within the law. The question could become moot if Thompson officially announces his candidacy before the FEC rules on the complaint against him.
Thompson already has one key GOP backer in Minnesota. Republican House Minority Leader Marty Seifert told Thompson that he will be happy to use his political organization for Thompson's benefit if and when he gets into the race.