I wonder why Luna opted not to play Chavez himself?

The directorial debut of actor Diego Luna, Cesar Chavez is a respectful, yet rather dry biographical drama focused on the titular civil-rights activist and his iconic nonviolent campaign against the unethical treatment of laborers by California farmers in the 1960s. In the lead role, Michael Peña delivers an earnest and quietly robust performance, and the film's social conscience is never in doubt, but there are several flaws which undermine its grand intentions. Among them is a general shortage of context as Luna and his writers rely too heavily on the viewer's presumed prior knowledge of Chavez. Another is a forced subplot involving Chavez and his anxious relationship with an estranged son; these scenes played as if they were shoehorned in at the eleventh hour in a desperate and ultimately failed bid to give an otherwise curiously detached picture a type of melodramatic personal dimension.

C+