Original post: Stephen Colbert has teased the possibility of announcing a run for president on Thursday, but there's a big reason he won't: campaign finance law would require him to shut down his beloved super PAC.

On Thursday, the Comedy Central host ignited a flurry of excitement behind tonight's show with the promise of a "major announcement," which hinted at a run for the presidency. "Colbert For President? Tune in Tonight" reads a New York Times headline. "Colbert mulls 2012 bid" reads Politico. A popular thread on message board site Reddit teamed with enthusiasm. "I was into Stephen Colbert being president before it was cool," a commenter said.

While anything is possible tonight, the smart money is on Colbert declining to enter the race because of the legal turmoil he would put himself through as the head of the super PAC Americans for a Better Tomorrow, Tomorrow, says Rick Hasen, professor of law and political science at the University of California Irvine's School of Law. "If Colbert declared himself a presidential candidate, he would no longer be able to run a super PAC and be intimately involved with it," he tells The Atlantic Wire. "Super PACs have to be completely independent of a candidate and the penalties would be very serious."

Hasen isn't kidding. Brett Kappel, counsel at the Washington, D.C. law and lobbying firm Arent Fox, put the potential legal costs in stark terms for us. Let's say, hypothetically, Colbert announces he will run and maintains his leadership of Colbert Super PAC. In that scenario, he would be subject to coordination complaints filed to the Federal Election Commission, which can result in excessive costs. "If someone files a complaint, the investigation takes a minimum of a year and requires all sorts of expenditures," Kappel told us. "They are extremely expensive cases to defend against and can be intensely time-consuming." Kappel, who has worked on cases taken to the FEC, said defending against such complaints can cost hundreds of thousands of dollars. (Those legal fees dwarf the actual cost of the penalty for coordinating with a super PAC: the minimum fine is $7,500.)

Of course, if Colbert was really committed to running, his lawyers at Caplin & Drysdale would tell him to dissolve the super PAC. "I'm sure Trevor Potter, who is an excellent lawyer, would say 'Stephen, I advise you to sever ties with the super PAC," said Kappel.

Colbert's political activity this year -- forming a super PAC, running ads in Iowa, testifying before Congress -- has primarily been about illustrating the boring but important issue of how corporations have been given near unlimited ability to influence elections. Forming a super PAC in the first place required the FEC to rule on the question of whether by airing The Colbert Report, Viacom was in effect making a contribution to his super PAC with airtime.