In Romney's Voucher Education Policy, a Return to G.O.P. Roots Mark Makela for The New York Times Mitt Romney at a charter school in Philadelphia in May. "Voucher" is a fighting word in education, so it may be understandable that when Mitt Romney speaks about improving the nation's schools, he never uses that term. Nonetheless, as president, Mr. Romney would seek to overhaul the federal government's largest programs for kindergarten through 12th grade into a voucherlike system. Students would be free to use $25 billion in federal money to attend any school they choose - public, charter, online or private - a system, he said, that would introduce marketplace dynamics into education to drive academic gains. His plans, presented in a recent speech at the U.S. Chamber of Commerce, represent a broad overhaul of current policy, one that reverses a quarter-century trend, under Republican and Democratic presidents, of concentrating responsibility for school quality at the federal level. "I will expand parental choice in an unprecedented way," Mr. Romney said, adding that families" freedom to vote with their feet "will hold schools responsible for results." His proposals are the clearest sign yet that Republicans have executed an about-face from the education policies of President George W. Bush, whose signature domestic initiative, the No Child Left Behind law of 2002, required uniform state testing and imposed penalties on schools that failed to progress. Now Mr. Romney is taking his party back to its ideological roots by emphasizing a lesser role for Washington, replacing top-down mandates with a belief in market mechanisms. It is a change driven in part by Tea Party disdain of the federal government. In the Republican presidential nominating fight, candidates competed in calling to shut the Education Department. Mr. Romney, who never went that far, also seems hemmed in politically by the fact that President Obama promotes many solutions that were once Republican talking points, including charter schools and teacher evaluations tied to test scores. "There's not much left for Republicans to be distinctive about," said Chester E. Finn, Jr., president of the Thomas B. Fordham Institute, an education policy group. "The one line the Obama folks have refused to cross is the voucher line" - that is, allowing students to use taxpayer money to attend any certified school, even a private school. Specifically, Mr. Romney proposed to change federal payments made to schools with large numbers of poor and disabled students into an individual entitlement. Students would take a share of the $25 billion in two federal programs to the school of their choice. He would also extract the federal government from intervening to turn around the lowest performing schools, which has been a chief focus of the Obama administration. Instead, to drive improvement, Mr. Romney would have schools compete for students in a more market-based approach to quality. "This is the best motive to reform there will ever be - if you give parents the ability to vote with their feet," said Tom Luna, Idaho's superintendent of schools, who is an adviser to Mr. Romney. But there is limited evidence in the real world of schools improving much as they compete for students, according to education experts. One notable skeptic is Margaret Spellings, a former education secretary under Mr. Bush, who this year was an informal adviser to Mr. Romney. She said she withdrew once the candidate rejected strong federal accountability measures. "I have long supported and defended and believe in a muscular federal role on school accountability," Ms. Spellings said. Vouchers and choice as the drivers of accountability - obviously that's untried and untested. Although offering economically disadvantaged children an escape from a failing neighborhood school may be a matter of fairness, Mr. Romney's argument is broader: choice, he said, will promote competition for students and, like a rising tide, lift all schools. One recent study of a Florida program offering private school vouchers to low-income families found that test scores at public schools, faced with competition, went up. But critics say that the improvements are small, and that the idea is shaped by ideology more than evidence. "Romney is on poor empirical ground in making a claim based on competitive effects," said Christopher Lubienski, an education professor at the University of Illinois. James Kvaal, the policy director of the Obama campaign, accused Mr. Romney of seeking to "stop the clock on decades of reform by no longer insisting action be taken when a school has been struggling for years." Advocates for vouchers say they will have a larger impact if they become more widespread.