Who Should Play Teddy Kennedy?

I hate to start the casting ball rolling so soon after a person's passing, but somebody's got to. So in the inevitable movie about Teddy Kennedy, who should play the Massachusetts Democrat who achieved so much (though USA Today's Wednesday headline, "Kennedy Made Massachusetts Larger Than It Is," was a tad unfortunate)?

*Leonardo DiCaprio. He's got the biopic thing down pat, and would probably be even better in this than in his rumored role as Sinatra.

*Brad Pitt. Don't laugh. He's proven to be versatile enough to pull this off.

*Gerard Butler. Why not? He's in every other movie.

*Michael Fassbender. He's Lieutenant Hicox in Inglourious Basterds. A friend told me he'd be perfect as Teddy. My friends don't lie.