New Jersey Gov. Chris Christie and U.S. Rep. George Miller, D-Calif., went toe-to-toe today on the role of teachers’ unions in the lackluster state of American education, and how much unions are, or are not, standing in the way of change.

The exchange caught fire nearly an hour into a National Education Town Hall, at George Washington University, sponsored by the makers of the “Waiting for Superman” documentary. The back-and-forth came just in the knick of time because the town hall was on its way to being a snoozer. (Case in point: The first question from the moderator of the five-person panel asked Christie to name his favorite teacher and why.)

In the duel of words between Christie and Miller, here’s a recap:

Christie, who doesn’t mince words, says, “The single most political force is the teachers’ union fighting this. They are the people to blame for the lack of change.”

Miller, who is certainly not the unions’ biggest champion, replies: “That’s too simplistic.”

Then, the conversation gets a bit heated when a question comes to the panel via Twitter that asks for advice for teachers who don’t “feel supported in advocating for more progressive schools.”

Miller talks about how there are great models out there for teachers who want to be a part of stronger reforms, from charter schools to public-school choice, and in programs like Teach for America.

Christie retorts: “You are talking about an infinitesimal amount of the teaching opportunities in America. It’s infinitesimal, congressman, and you know it.”

To which Miller responds: “To suggest [improving schools] can’t be done because of the unions is to cave into the argument that it can’t be done.”

And then Christie says: “You need to stand up and tell the truth ... stand up and say, ‘Enough.’”

To watch the full exchange, which really gets going at about minute 54, fast-forward the video below to minute 51, when the question is first posed. The other panelists were Harlem Children’s Zone founder Geoffrey Canada, U.S. Sen. Michael Bennet, D-Colo., and Tony Miller, the deputy education secretary, who was a stand-in for Secretary of Education Arne Duncan, who couldn’t make it.

Photos: Top: U.S. Rep. George Miller, D-Calif., speaks during the National Education Town Hall on May 11 in Washington, D.C.; Right: New Jersey Gov. Chris Christie (Andrew Councill for Education Week)