Jason Schwartzman possesses a likeness to Abbie Hoffman, the co-founder of the Youth International Party, beyond just looks. Schwartzman made his acting debut playing the mischievous Max Fischer in Rushmore and, ever since then, his characters are usually up to something.
Anton Yelchin has recently taken a shine to acting in sci-fi action movies like Star Trek, but if we look back to his Charlie Bartlett days, he's definitely capable of playing nonconformist Rennie Davis.
Daniel Bruhl has worked with director Paul Greengrass in the past for Bourne Ultimatum and has the scruffy/tough-guy look to play anti-war leader Jerry Rubin. Bruhl has also starred in films about activists before, like Goodbye Lenin! and The Edukators, and played a slightly strange activist, the fairy, in Julie Delpy's Two Days in Paris and Two Days in New York.
We choose Paul Dano to play the odd man out in the bunch, David Dellinger, who was a wealthy Yale graduate and pacifist. Dano is a versitle actor who's starred in everything from Little Miss Sunshine to There Will Be Blood, but his style and unique appearance make us think he would fit this misfit role.
Like Jason Schwartzman, Jim Sturgess possesses a likeness to his character Tom Hayden (an activist who went on to marry Jane Fonda). His roles in Across the Universe and 21 make us think he can handle playing a hippie gone rogue.
Jack Huston has yet to make it big on the big screen (we're not going to count his role in Twilight), but we think the role of Lee Weiner from the Chicago 7 could be his breakthrough. We know he can play a gangster with a heart of gold from his two-faced role (literally) in the HBO show Boardwalk Empire, and we can see him playing a passionate activist.