Michelle Obama set just the right example as the mom in chief. She made no speeches about Afghanistan or the stimulus for the global economy, but returned from a boffo trip to London and Europe with better press notices than her husband. She visited a girls' school in England, dispensing hugs and air kisses, and charmed heads of state from two dozen nations. No first lady has so dazzled Europe since Jackie Kennedy took her husband along when she conquered Paris and put Charles de Gaulle at her feet.

Nevertheless, Michelle hurried back to Washington early on Sunday for first things first, to get Malia and Sasha ready for the school bell on Monday morning. Despite a grandmother in residence at the White House and a staff of thousands -- well, dozens, anyway -- a mom in chief knows that only she can enforce the discipline that every schoolchild needs and craves.

When she and the president catch up on what they missed in Washington, they should read the latest performance evaluation of the Opportunity Scholarship Program, a school voucher program in their new hometown. It should be of particular interest to a mom who gives the education of children, her own and others, pride of place at the top of the agenda.

Seventeen hundred Washington children attend private school with vouchers under this scholarship program, and two of them attend Sidwell Friends School with the Obama girls. Unlike most programs and schemes in the nation's capital, this program has human faces -- all of them children's -- and the evaluation report will influence education policy across the country.

The Opportunity Scholarship Program is small stuff in Washington, where trillions of dollars are thrown around like Frisbees, but the program drew national notice because a few sentences and paragraphs were tucked into the stimulus bill to abolish the program. Congressmen and figures in the new administration, who like the Obamas wouldn't dream of sending their kids to a public school in Washington, cheerfully killed a program for families not as fortunate as themselves. All in the name of high principle, of course.

The president and the Democrats say they killed it because there was no proof that it worked. But now there is. The evaluators found that scholarship students scored specific gains in reading -- by a half grade. That's no small increase. Math scores remained steady, and the scores suggest that further gains will follow as the students from deprived neighborhoods acclimate themselves to the more rigorous discipline of private schools. This is the change that hundreds of parents are eager to believe in.

"There are transition difficulties, a culture shock, on entering a school where you're expected to pay attention, learn, do homework," Jay Green, an education scholar at the Manhattan Institute, told The Wall Street Journal. "These results fit a pattern that we've seen in other evaluations of vouchers. Benefits compound over time."

Ninety-nine percent of the low-income students who have transferred from deprived neighborhoods are black and Hispanic. A long waiting list, with four applicants vying for each scholarship, testifies to the demand for the program. The $7,500 voucher is equal to slightly more than half of what the District government spends per student in the District's dreadful public schools. Despite the $14,000 the District spends per pupil in its public schools -- highest in the nation -- the District achievement scores are among the lowest in the country.

Vouchers are key to education reform, along with more charter schools, knowledge tests and merit pay for teachers. But the powerful teachers unions, the ventriloquists behind the congressional dummies on their laps, naturally oppose reforms that would impose accountability. The worst teachers know their weaknesses, and the protection of mediocrity becomes the first order of business for the teachers unions.

President Obama promised that he would support "what works for the kids," and now he has the proof that this specific program works. In addition to the statistical evidence, there's the reassurance, hard to measure but abundantly clear, for parents and their children to feel secure and safe in the program. The program takes them out of schools where learning is not often prized and where physical safety is often at risk.

No one begrudges the president and the first lady their choice of a good school for their children. They can easily pay for whatever they choose. But if Michelle, as the nation's mom in chief, keeps her silence as others kill a program enabling choice for those who can't easily pay, she invokes the ghost of Marie Antoinette -- the kids cry for the bread of knowledge; let them eat stale cake. They need more than a hug.