"WON'T BACK Down" jams a sharp stick into the hornet's nest of public education reform.

The result: a lot of buzz. Much of it concentrated on the movie's financing, put up by conservative money men through Walden Media.

Coincidentally, the movie advances a conservative reform, the idea of so-called "parent trigger" provisions, already law in four states (though yet to be used to reform a single school).

These laws permit parental majorities at failing public schools to trigger a conversion to a charter school - giving parents the right to remove union protections, fire teachers and administrators, change work rules.

"Won't Back Down" presents a utopian version of this - a single mom (Maggie Gyllenhaal) with a struggling child teams with a reform-minded teacher (Viola Davis) in a bid to take over their failing Pittsburgh public school (where 2 percent of kids go to college; at a private school nearby, 98 percent go to college).

In trigger-law reality, teachers tend not to be part of the process. In states where the laws exist, it's strictly parent-driven, and often opposed by the PTA and parents groups sympathetic to unions.

And opposed, of course, by unions - a big part of the story in "Won't Back Down." Holly Hunter is a union administrator charged with stopping the takeover. "Won't Back Down" spends a lot of time in union offices, and gives full voice to reasonable pro-union arguments advanced by leaders, who wonder: "When did Norma Rae become the bad guy?"

"Won't Back Down" is clearly and obviously a movie that advocates reform, but in an effort to present all sides of this complicated issue, bends over backward, sideways, frontways - to the point that it's like screenwriting yoga.

The movie at times drowns in exposition, even when it tries to channel this through character - Gyllenhaal's activist, for instance, falls for a pro-union teacher (Oscar Isaac) and they hash out their arguments over beer.

So it has some problems, like an overactive third-act plot, but it also has Davis, Hollywood go-to gal for bringing gravitas and emotional resonance to imperfect dramatic vehicles ("The Help"). She and Gyllenhaal cut through the spin and speechifying to carve out some affecting human moments.

Contact movie critic Gary Thompson at 215-854-5992 or thompsg@phillynews.com. Read his blog at philly.com/keepitreel.