Charter school proponents like to revel in their self-proclaimed boldness at rejecting public education orthodoxy: "It is hard to be here bucking against the system the way it’s always been done," Representative Eric Petigrew proudly bemoaned at a press conference announcing his charter school legislation, echoing countless other pro-charter school "progressives" before him.

Yet inherent in the very notion of charter schools is another orthodoxy, one so deeply entrenched in American culture that few elected officials seem capable of even mustering the imagination, let alone the will, to challenge it. The fundamental and driving principle behind charter schools is that by giving students and parents a choice, competition will force improvements in public education as a whole. As such, the charter school movement is as pure an expression of America's blind faith in the magic of markets, as anything you'll find in field of the economics. The unchallenged assumption behind charter schools is that competition is good.

But consider the contrary—and given that public schools have had stiff competition from their private and parochial counterparts since the inception of public education in the 19th century, there is plenty of evidence to consider.

Imagine for a moment that we outlawed private education, and mandated that all children between the ages of 5 and 18 attend their neighborhood public school until they graduate or age out. Instantly, average test scores would rise. That's just math.

Public schools must take all comers, while most private schools have minimum admissions standards beneath which students simply are not welcome, be it due to academic ability, special needs, or disciplinary issues. Students at private schools are more likely to be prepared to learn, and to have parents involved in their educations. Drive these students from their more exclusive schools back into the public school system, and average aggregate test scores will surely rise. You know, like magic.

But behind this test score facade, the schools themselves will improve too, for when parents of means and/or motivation have no other choice but to enroll their children in their neighborhood school, they will not only demand improvement, they will have the financial and personal resources to back it up. These are parents, on average, who are more willing and able to invest time and money in their children's schools, and who, on average are more highly educated themselves. And, when all our children are dependent on the same state-financed public education system, it becomes much easier to build the political consensus to force our lawmakers to properly fund it. Private schools allow many families to opt out of the public school debate, arguably to the detriment of public education as a whole.

Now, I'm not proposing that we should outlaw private education, but it is reasonable to suggest that doing so might make our public schools better. And if eliminating private competition would arguably improve our public schools, isn't it also reasonable to suggest that creating more competition through charter schools could actually make the remaining public schools even worse, not just by diverting public resources—something, at least, that private schools generally don't do—but by cherry-picking the best students and the most motivated families, leaving behind those who, in aggregate, are more difficult and expensive to educate?

Go ahead, challenge this thesis that competition is bad for public education. Pick it apart all you want. But don't you dare do so while leaving the opposite thesis entirely unchallenged: that competition is always good.

See, that's the thing about charter schools that is too often absent from the public debate. Pettigrew's charter school legislation is an education reform without education reforms, that proposes no theory, no formula for restructuring the classroom or the curricula. Instead, it proposes creating a competitive marketplace for public schools—competition through which better schools will magically arise. It is a reform that is based entirely upon an unchallenged assumption, even in the face of a growing body of evidence that suggests that this assumption is wrong.

There are no comprehensive, peer reviewed studies that conclude that, on average, students in charter schools perform better than their counterparts in traditional public schools. In fact, there is evidence that about a third of charter school students do worse! That is why former Assistant Secretary of Education Diane Ravitch, who championed charter schools under the George H.W. Bush administration and throughout the 1990s, has since become one of the movement's harshest and most vocal critics. "[T]he promise has not been fulfilled," Ravitch wrote in a March, 2010, guest column in the Wall Street Journal, in which she cited a pro-charter-funded study to back her conclusion that "deregulation and privately managed charter schools were not the answer to the deep-seated problems of American education."

What we need is not a marketplace, but a coherent curriculum that prepares all students. And our government should commit to providing a good school in every neighborhood in the nation, just as we strive to provide a good fire company in every community.

On our present course, we are disrupting communities, dumbing down our schools, giving students false reports of their progress, and creating a private sector that will undermine public education without improving it. Most significantly, we are not producing a generation of students who are more knowledgable, and better prepared for the responsibilities of citizenship. That is why I changed my mind about the current direction of school reform.

Ravitch, to her credit, allowed real-world results to ultimately challenge her own assumptions about the inherent efficiency and infallibility of the market. Here's hoping local charter school advocates like Pettigrew will allow the facts to challenge their assumptions as well.