Back-to-school supplies are on sale and the annual report on schools that are not making adequate progress is due out any day (expect another rise in falling performance), so this is a good time to look at the performance of Minnesota's charter school movement, which was going to lead us all into a bright 21st century for better, smarter public education.

Oops. Not doing so great there, either.

Improving learning outcomes for students of color? Nope.

Outperforming traditional public schools on achievement tests? Nope.

Pointing the way for the education of the future? Not so much.

It would be easy to argue that the charter school movement has fallen flat, and I have said as much before. But the charter school crusade has grown too large and expensive to dismiss. It is eating into severely limited funding for education and has blurred the lines between church and state (and not just at one Muslim school, but among many charters loosely basing their educational approaches on religious values whose adherents think they should get public tax dollars to inculcate them).

More than that, charter schools have created a huge tax-supported playpen where entrepreneurial start-up schools have been loosely supervised and unscrutinized by education officials who are accountable to the approval or rejection of taxpayers.

Minnesota was the first state to allow charter schools (in 1991), which were designed to overcome the limitations of an education system that had become a sacred cow. Today, you can't find a holier cow than the charter school movement. Any questions can get you branded as a stooge for unionized teachers, big gummint and mandatory euthanasia for free thinkers. Guilty, guilty, hmmm ... maybe!

Nevertheless, it is clear that Minnesota's charter schools (almost 150 of them now, with 28,000 students) are as much a part of our educational problem as they were supposed to be a solution. Many charters have been beset by management problems, undertrained staffs and a lack of adequate financial controls. The furor over TiZA, the troubled Muslim charter school in Inver Grove Heights, is only one example of a much broader mess: Too many charter schools do not get adequate oversight, especially from one system that works -- elected school boards that answer to voters.

After nearly two decades of "experimenting," charter schools need to be held to stricter financial controls, educational performance standards and public accountability. It is also past time to put a cap on the number of charter schools, and the present 150 is more than enough. The urgent need now is not for more charter schools, but better ones. And that requires shutting down the bad ones.

The Legislature took an initial step to tighten controls last spring with passage of a reform measure setting up a more rigorous review process and requiring the state Education Department to enter into performance contracts with charter schools. But the law lacks serious teeth, and the problems may be larger than the law can bite off.

More than 80 percent of charter schools were found to have serious financial or management problems during 2007, according to a review of state records done by the liberal think tank Minnesota 2020. That group's executive director, John Van Hecke, finds it ironic that charter schools, built on a promise to make education more responsive, have avoided the scrutiny traditional public schools must face.

"When they were launched, the battle cry was, 'We'll be better than traditional public schools,'" he said. "Now it's, 'Don't hold us to the same standards as traditional schools.' But the public clearly is demanding more and more accountability over how its money is spent. And the answer is more and more oversight, from the Education Department and the Legislature."

In addition to millions spent on per-pupil aid for charter schools, up to $1,200 per pupil is spent in state assistance to help buy or rent charter school space (this at a time when public enrollment is shrinking and surplus education buildings stand vacant). These "lease aid" payments will balloon by 23 percent this biennium, to a whopping $85 million, and much of that total is going into a muddled mess where payments continue even after buildings are paid for and tax-paid real estate winds up owned not by the public but by the charter schools themselves.

State Sen. Kathy Saltzman, a Woodbury DFLer, sponsored the recent legislation to tighten charter controls. She says the law is just a start and that more changes are necessary. Charter schools are here to stay, she says. But so are demands for accountability.

"We all have a responsibility to make sure each tax dollar is spent wisely," Saltzman says, sounding very much like the early advocates of charter schools who criticized traditional schools. "That's our job."

Nick Coleman is a senior fellow at the Eugene J. McCarthy Center for Public Policy & Civic Engagement at the College of St. Benedict/St. John's University. He can be reached at nickcoleman@gmail.com.