Yes, they're claiming the subpoena has to do with Mike's recent trip to Cuba for the filming of "Sicko," but it's hard for me to believe that there are no other underlying motives:

Filmmaker Michael Moore revealed on Thursday's "The Tonight Show" with Jay Leno that the Bush Administration had served him with a subpoena regarding his recent trip to Cuba made as part of his new film, Sicko.

Moore told the audience that he was notified of the subpoena backstage.

"I haven't even told my own family yet," Moore remarked. "I was just informed when I was back there with Jay that the Bush administration has now issued a subpoena for me."

Moore declared that the subpoena was unwarranted, saying, "this was a work of journalism."

"I was there to help them and now I’m going to face this further harassment from the Bush people," Moore said, according to a transcript. “Aren’t they busy with something else?"

Indeed. For more on the story, check out Michael Moore's website (h/t to Crooks & Liars).