If you plan to see the new Matt Damon film “Promised Land,” stop reading this column right now because I’m about to spoil the hell out of it.

Not that I’d recommend the film. No matter what your political persuasion, you will likely find it frustrating. It is a deeply earnest work that wants to say something profound on a topical issue — then completely undermines its own message. “Promised Land” is a useful reminder that although Hollywood is often described as a liberal enclave, it isn’t necessarily much of an asset to liberal causes.