It is safe to say that America’s public schools are not exactly basking in the glow of achievement and approbation. While the education establishment continues to block fundamental state and federal reform efforts, public disaffection with the country’s system of public education is at an all-time high. Business leaders are increasingly vocal in their criticism of public schools. Journalists are not as eager as they used to be to parrot the National Education Association’s line on school reform. Activists across the country have won important victories–from privately funded voucher plans to local and state choice initiatives–against sloth and bureaucratic intransigence. Students in Indiana, Michigan, Maryland, Georgia, and Texas already receive or will soon receive vouchers from businesses and foundations to attend local private schools. Private firms are managing public schools in several states, and Chris Whittle’s Edison Project plans a nationwide network of for-profit schools to revolutionize American education.

But even as public elementary and secondary schools increasingly draw fire from every side, one government-run education program continues to attract substantial political and public support: Head Start. Both liberal Democratic and conservative Republican governors tout it. Even disgruntled, frustrated business leaders–willing to back revolutionary change in K‑12 education–nonetheless sing the praises of Head Start, a Great Society program that spends billions of dollars a year to provide educational, developmental, medical, and nutritional services to poor preschoolers.

Head Start’s impressive public relations triumph should surprise no one. The program’s boosters base their appeal on a sensible-sounding premise: if we can intervene early in poor children’s lives, give them a “head start” on developing into good students and well-adjusted teens, then many of them will not grow up to be welfare mothers, deadbeats, or criminals. With every social catastrophe averted, we’ll save ourselves a lot of worry, trouble, and money. That is the essence of “fiscal conservatism,” advocates say, since a little “public investment” now will pay huge dividends in tax revenues and forgone social spending later.

Head Start’s sales pitch works wonderfully. Business leaders like the investment rhetoric. Journalists love all the photo opportunities with cute, smiling kids. Teachers’ union officials and other leaders of the education establishment relish the chance to extend their reach beyond kindergarten into the preschool years. Big-spending politicians enjoy touting a program that actually appears to work. Fiscal conservatives prefer Head Start’s relatively low price tag (in comparison with the rest of the education establishment’s agenda: higher teachers’ salaries, smaller class sizes, bigger buildings, equalization of spending for small or rural school systems, and so on).

The pitch works, despite the fact that Head Start’s major selling point–early intervention can prevent future dependence and delinquency–rests on several shaky foundations. First, it assumes that policymakers can draw sweeping national conclusions from studies of a few unique (and non-Head Start) preschool programs. Second, it assumes that children’s futures are fundamentally malleable, that a brief outside intervention can make an indelible impact on most children’s lives despite the continuing influence of both heredity and environment. And third, the Head Start thesis assumes not only that successful early intervention is possible but that government is an appropriate and effective provider of it.

All three of those propositions are false. Head Start’s hucksters, all smiles and promises, have sold the public on a shiny prototype that bears little resemblance to what will actually be provided and, upon closer examination, is an empty shell with nothing under the hood. Before American policymakers sign anything, they’d better take a good look at what they’re getting.