The documentary No Safe Spaces picks up a discussion it presumes you’re already engaged in, led by conservative talk radio host Dennis Prager and comedian and podcast superstar Adam Carolla. The two men start by talking about how different they are from one another, an assertion soon undermined by the fact that they seem to agree about absolutely everything.

The biggest thing they agree on is how tragic the erosion of free speech is at American colleges. The central premise of the documentary is that vocal, sometimes violent left-wing campus activists are silencing opposing voices on campuses. It’s a situation the film firmly establishes with example after example, many of them tracing the career destruction of seemingly innocent people who stood up against what they saw as excesses of identity politics.

The film shares its title with a paid speaking tour by Prager and Carolla (who enjoys showing off the excesses of his wealth now and again), which has itself been protested. But whether you like or dislike the self-promoting hosts — or whether you’ve heard of them or not (I had not) — the documentary raises a lot of vital questions worth examining. Should all speech be free? When does the exercise of the right to protest infringe on the right to speak? And, most centrally, should the young adults on college campus be protected from all potential emotional harms, or should they instead be taught to confront what they may disagree with, as part of the learning experience?

The film has its own answers, none of which is sufficient to the conundrum, but viewers are still encouraged to give these guys a listen and discuss solutions of their own. First-time filmmaker Justin Folk has put together a slick package, full of stimulating case studies and intelligent assessments of what “freedom of speech” should mean in practice.

The film also has some bad gags (a cartoon assassination of the Bill of Rights) and some big gaps, beginning with the shoddy introductions of its hosts. There’s equally incomplete background on controversial figures including Ben Shapiro, Jordan Peterson, and others (more people I had to look up later). Some of the people hounded on campuses are also incompletely introduced — for example, a besieged UC Berkeley student senator says all she did was abstain from a vote, but the film fails to tell us that what she declined to support was a resolution supporting transgender rights (I looked that up too).

In the end, the movie makes a decent case for “no safe spaces” — that is, favoring even heated, occasionally uncivil debate over the silencing of unpleasant speech. But it also suffers somewhat from the “very fine people on both sides” problem: It acknowledges that some speech can be censored as inciting violence but doesn’t want to grapple with any messy definitions. It condemns people who rush to Hitler comparisons, then doesn’t hesitate to make its own comparisons to totalitarianism. Most tellingly, it never tries to define the divide between speech and action — talk, good; breaking things and punching people, bad — that is a necessary starting point to finding workable solutions.

Prager and Carolla seem like decent guys who are genuinely concerned about a real problem, and they earn some admiration for exploring it, with Folk, in considered detail. But they’re also professional talk show hosts who thrive on the debate and have no obligation to offer any solution more practical than “have courage.”

Grade: B. Rated PG-13. Opens Nov. 8 at the Grail Moviehouse.

(Photo: Justin Folk, courtesy of Atlas Distribution Co.)