César Chávez, a new biopic about the labor activist, elicited applause and cheers, bordering on the ecstatic, at a recent screening for critics and members of a local film society.

Featuring a repertory cast led by Michael Peña, Mexican director Diego Luna's pic is about the five hard, lean, brutal years it took Chávez, his wife Helen (America Ferrera), lawyer Jerry Cohen (Wes Bentley), and a group of volunteers to organize the United Farm Workers, initially called the National Farm Workers Association, in Delano, Calif., in the 1960s.

As history lesson, César Chávez is inspiring, especially welcome in an era when, at least according to Chávez's spiritual heirs, corporate power once again trumps workers' rights.

As drama, however, it is an amateurish mess, with faltering direction and wooden acting.

The film raises an old debate: Should we praise didactic art for its uplifting message, or critique it as we would any other work?

The answer continues to evade us.

César Chávez ** (out of four stars)

Directed by Diego Luna. With Michael Peña, America Ferrera, Rosario Dawson, Yancey Arias, Wes Bentley. Distributed by Lionsgate.

Running time: 1 hour, 41 mins.

Parent's guide: PG-13 (violence, profanity, smoking)

Playing at: The PFS Theater at the Roxy