For anyone who needed to gauge just how far the demonization of teachers unions has gone, the final episode last spring of TV's "Law and Order" -- the real one, not the new L.A. knock-off -- was instructive. Bracketed by the customary soundtrack "cha-chungs," the story concerned a loony former substitute teacher bent on blowing up the high school where he'd subbed. But the real heavy was a weaselly union lawyer who blocked the cops' access to the teacher's whereabouts, on the grounds of -- well, something like Marx's labor theory of value, or Walter Reuther's argument for co-determination at General Motors; it wasn't entirely clear which. Said weaselly lawyer crumbled, of course, when confronted with Sam Waterston's righteous rectitude.

After that, the new Davis Guggenheim movie "Waiting for Superman," which merely asserts that teachers unions are to blame for the deficiencies in American education, is almost a letdown. Teachers as terrorists, Al Shanker as the enabler of al-Qaeda -- now, there's a story the whole family can enjoy.

(Watch a video of D.C. Schools Chancellor Michelle Rhee discussing the D.C. Public School system.)

The picture Guggenheim paints isn't quite as lurid as that, but it's ultimately no more accurate. In the world of "Waiting for Superman," every public school is a disaster, every charter school is a rigorous (but nurturing) little Harvard or Oxford, and the blame for the plight of public schools and the paucity of charter schools can be laid entirely on the unions' doorsteps. You'd never know from the film that charter schools produce test results that aren't any better than those of public schools, or that the teachers at a number of charter schools -- including charter schools that do produce high test results -- are, horror of horrors, unionized.

Still, the narrative that education reformers and teachers unions are eternal and implacable enemies is a hardy one, and one that Washingtonians in particular may well believe after four years of pitched battle between Schools Chancellor Michelle Rhee and the D.C. teachers union. The intensity of the local battle might blind them to the experience of cities where the school district and the union have jointly embraced a reform agenda, even including a version of merit pay. And yet, such an agreement -- an impossibility, if we are to believe the conventional narrative -- was reached just two weeks ago in the faraway city of Baltimore.

(For more opinions on the trouble with America's education system, read Jo-Ann Armao's "Is the public turning against teacher unions?" and a Post editorial "Education jobs bill is motivated by politics.")

The Baltimore contract, on which teachers will vote Oct. 14, bases pay on a combination of professional development training, joint management-teacher evaluation and measured student achievement. As Shanker, who headed the American Federation of Teachers (AFT) from the 1960s through the 1990s, long advocated, this system establishes a career ladder for teachers -- a four-step progression from "standard teacher" to "lead teacher" -- that rewards excellence while still recognizing seniority. The criteria by which teachers will be judged will be aligned with state standards that Maryland is developing in which 50 percent of a teacher's score will reflect student achievement.

The best teachers under this contract could make more than $100,000. That's chump change for one of those brilliant young Goldman Sachs associates who creates wealth by peddling toxic paper to rubes, but it's nonetheless a step toward reconciling recompense with our social needs.

"Contracts are a good way to make systemic change," says Randi Weingarten, president of the AFT. "In Baltimore, we've established a career ladder with different lanes and aligned compensation with it." Teachers will get more say over what's taught in their classrooms -- and be rewarded for positive results.

While Baltimore's contract is groundbreaking, the AFT, by Weingarten's estimate, has contracts that include elements of the Baltimore deal in 50 to 60 districts around the country. Representing more than a million public school teachers nationwide in the current system while working to change that system is no easy task, but it's one that the AFT is increasingly trying to perform.

That probably won't diminish the scapegoating of the union by those who believe that unions can't possibly back reform or that we can't afford decent teacher pay or pensions in an age of budget deficits. Blaming teachers for the dysfunction of inner cities and the decline of American industry lets a lot of other, more culpable, parties off the hook. But if our goal is to improve education, and not just exculpate ourselves for our social and economic decline, we should be applauding the Baltimore contract and the reformers, in think tanks, district offices, classrooms and, yes, unions, who seek to better our schools and our country.

meyersonh@washpost.com