Romney rolled out his education plan on Wednesday. The setting was the vault-like confines of the U.S. Chamber of Commerce, where Latino businessmen and women applauded his speech attacking teachers unions and federal overreach.

Mitt Romney participates in a 6th grade language class at Universal Bluford Charter School in Philadelphia. (Mario Tama/Getty Images)

On the surface, it seems like an idea that Republicans have embraced for some time, by making funds portable to encourage school choice. But Rick Hess of the American Enterprise Institute believes that the policy exemplifies the kind of heavy-handed federal intervention that Romney wants to eliminate elsewhere.

“In terms of school choice, he clearly overreached...having the feds mandate it regardless of state context,” says Hess, who is enthusiastic about many other parts of Romney’s education plan. Certain states and local governments have experimented with similar open-enrollment policies, which allow students to enroll in schools outside of their own district. But Hess believes that Romney’s federal mandate would disregard the particular needs of individual states and communities. Popular schools, for instance, might be flooded with voucher-bearing students from outside the district, angering local homeowners who’ve made a direct investment in the local schools. “It’s destructive to brush aside concerns from communities,” Hess adds.

The Romney campaign is trying to assuage the concern that open-enrollment would drain some schools’ resources unfairly. “Obviously, with an open enrollment plan, there needs to be a mechanism that addresses the capacity of the schools in all of the districts of a state,” Oren Cass, Romney’s domestic policy advisor, said in a call with reporters Wednesday. But neither Romney’s white paper nor Cass explained how exactly the federal government — or anyone else — would prevent this from happening.

The proposal, by contrast, has heartened some liberal education reformers who’ve long championed open enrollment that focuses on public schools. “If various caveats are satisfied, that would put Romney to the left of Obama on public school choice,” says Richard Kahlenberg, a senior fellow at the Century Foundation. But that’s a big “if,” he cautions.

For example, under open enrollment, low-income students would need funding for commuting to schools outside of their district. But the Romney campaign says his plan will include no new funding for education, and Romney himself has endorsed the Ryan budget, which makes draconian cuts to education spending overall, though it doesn’t single out K-12 for specific reductions. So it’s unclear how Romney would address the transportation issue without additional government spending.

What’s more, without a significant federal investment, vouchers are unlikely to be sufficient to cover private-school tuition for low-income students. Romney points to the DC Opportunity Scholarship Program as a model, for instance, but it’s a program that would be difficult to scale up. “Private schools can afford to take a few students for a $7,500 [scholarship], but at Sidwell Friends, the tuition is $35,000. As a model for the nation, that’s nonsense,” says Kevin Carey, policy director for Education Sector, an independent think tank.

Finally, in places that have implemented some version of open-enrollment — in Boston, for instance — “there are long waiting lists” for the desirable schools, Kahlenberg explains, and it’s unclear what criteria Romney would let schools use to turn prospective out-of-district students away.

Meanwhile, critics of open-enrollment point out that vouchers won’t make a difference for low-income students in areas where quality schools — whether public, charter, or private — are hard to find. “Cities tend to forget this, but in Scott County, Indiana...nobody’s building a private school there, a charter there,” says Carey. Romney does promote digital schools as one alternative, but that’s not a comprehensive solution, partly for the youngest students, Carey adds. In other words: what good is school choice if there are no good schools to choose from?

Ultimately, both supporters and critics of Romney’s education plan want the former Massachusetts governor to explain how he plans to enact his school choice without significant additional spending. “Given that [Romney] doesn’t want them to spend more money, while launching new program, it’s the question of — well, what are you doing?” Hess concludes.