It’s easy to understand why several prominent GOP Senators, including Sens. Lamar Alexander, Mitch McConnell, Rand Paul, and Marco Rubio, are sponsoring federal school voucher legislation. State-level voucher programs have raised student achievement, increased high school graduation rates, and boosted college matriculation. School choice programs are also market-based initiatives that aid and appeal to low-income voters. As Senator Paul argued:

“School choice for low-income parents and students across America is a way out of the poverty cycle,” Mr. Paul said in a statement. “Allowing Title 1 funds to follow the student creates an opportunity for students to get the most out of their education in the best environment possible.”

Moreover, a recent survey from Harvard University’s Program on Education and Governance found a high level of support for expanded school choice programs. All that said, the GOP should resist the temptation of a federal voucher system.

Even setting aside the question of constitutionality (education is not listed in the Constitution as one of the federal government’s enumerated powers), there are practical reasons for being skeptical about increased federal involvement in America’s education system. It is very likely that a federal voucher program will lead to increased federal regulation of private schools over time. While there’s no law of the cosmos that states that federal dollars must come with strings attached, they most often do. And while the GOP legislators proposing the vouchers will likely keep regulations light at the outset, when the political pendulum swings—as it inevitably will—opponents of vouchers might find that it’s politically easier to add regulations to the program than to kill it outright. Once private schools become dependent on the federal money that their students bring with them, the vast majority will accept the new regulations rather than forgo the funding.

Instead of playing with federal fire, the GOP should embrace federalism. As David Boaz wrote in the Cato Handbook for Congress a decade ago, the case against federal involvement in education:

is not based simply on a commitment to the original Constitution, as important as that is. It also reflects an understanding of why the Founders were right to reserve most subjects to state, local, or private endeavor. The Founders feared the concentration of power. They believed that the best way to protect individual freedom and civil society was to limit and divide power. Thus it was much better to have decisions made independently by 13–or 50–states, each able to innovate and to observe and copy successful innovations in other states, than to have one decision made for the entire country. As the country gets bigger and more complex, and especially as government amasses more power, the advantages of decentralization and divided power become even greater.

School choice programs have been expanding rapidly among the states in recent years (albeit not as rapidly as I would like). Supporters of school choice should be encouraging that trend, working hard at the state level to expand educational opportunities. Expanding choice all across the fruited plain in one swoop may be tempting in its immediacy, but it’s not worth the price.