There should be a test.

What, you have a problem with that?

As President George W. Bush said, “You don’t like tests? Too bad.”

Here’s the test: All educators and lawmakers, and parents for that matter, should watch the devastatingly good documentary “Waiting for Superman.” If you don’t cry or slam your first on the coffee table in the final minutes, as you watch grade-schoolers endure a lottery system to determine whether they’ll attend college-prep charter schools or neighborhood dropout factories, you don’t get to vote on education issues — or raise kids.

This isn’t some obscure art-house film. One even can rent it now from a Redbox right here in Carroll.

With a sharpshooter’s eye for detail, filmmaker Davis Guggenheim’s “Superman” gives us the view of American education from 20,000 feet, and then personalizes it with the stories of families — white, black and Hispanic for those keeping score on such things. The personal account that tugged at me was watching California gradeschooler Daisy, who aspires to be a doctor or veterinarian, riding in the backseat of her dad’s car, tears forming in her eyes, after the bouncing lottery balls don’t go her way.

Guggenheim, who won an Academy Award for directing the Al Gore star vehicle “An Inconvenient Truth,” isn’t giving us slapdash liberalism with “Waiting for Superman.”

In fact, the thesis of the movie is provided directly: you need to keep two competing thoughts in your mind at the same time. 1) Teachers are a national treasure. 2) Teachers unions are the blockade to meaningful change in American education.

The film is fuel for what is already happening in Florida, Idaho, Illinois, Nevada and New Jersey where Republican governors and their allies are seeking to deep-six teacher tenure — a system originally started in the turn-of-the-century New Jersey and expanded since to give K-12 educators a virtually impenetrable shield from dismissal. In March, New Jersey Gov. Chris Christie’s education department will put forward a plan that doesn’t reach for full elimination of tenure but ties teacher pay to other measures, such as test scores, observation, student and peer review.

Guggenheim’s film notes that only 1 in 2,500 teachers is ever fired. Earlier in my career I spent years covering the Ames public school system, as well as Carroll’s. I can recall only one teacher being fired (without financial or legal backlash), and that was for sexual abuse of a child. Said teacher is still in the state’s prison system.

Iowa Gov. Terry Branstad has expressed his admiration of Christie and Indiana Gov. Mitch Daniels (the latter whom I would expect Branstad to endorse should he seek the presidency).

Will he follow Indiana and New Jersey on teacher tenure?

No serious discussion so far, says State Sen. Steve Kettering, R-Lake View, whom I asked about the matter. Kettering sees the need, though, for a shift from the automatic increases and protections of tenure to more performance-scaled salaries.

“I think we need to get some sort of merit-based pay into that,” Kettering said.

On a conference call with other media last week I asked U.S. Sen. Tom Harkin, D-Iowa, simply if he thought it was too difficult to fire poor teachers. He said that’s hard to answer.

Instead, Harkin, a schools leader in the Senate who met with President Obama just days ago on education, said he is highly engaged with an elementary and secondary education bill in which he wants to provide for a pipeline or support system for getting good principals in more schools.

“After all these years I’ve become convinced that one of the key elements in getting schools turned around and making them better is who the principal is and how well-trained the principal is,” Harkin said.

Harkin wants to take examples of what accomplished principals did and hold them up as what lower-achieving schools should adopt through incentives for training principals.

That’s in line with “Waiting for Superman,” which shows us the remarkable success of schools with strong principals.

But at the end of the day it does come down to teachers. And it’s just too hard to scrub the bad ones from the system.

Republicans in Iowa — and Democratic allies — have an opening on this. And they have a super movie with which to sell the stripping of K-12 teacher tenure.