The House of Representatives narrowly approved the nation's first federally funded school voucher plan yesterday, endorsing a five-year pilot program for at least 1,300 children in the District in what supporters called "shock treatment" for the city's struggling public education system.

The Republican-backed measure, which would award private tuition grants worth up to $7,500 per pupil starting next year, passed on a nearly party-line vote of 205 to 203. The result was not the decisive victory proponents had sought, however. House Republicans were forced to postpone a final vote until Tuesday as supporters trickled away for the weekend after a five-hour debate and numerous skirmishes.

Both sides prepared to ratchet up the fight in the Senate, which will vote as early as next week on similar legislation, part of the District's $ 5.6 billion 2004 budget.

Yesterday's slender victory, coming after recent defeats of voucher proposals in state referendums, was a breakthrough in the nation's capital for a coalition of conservative and religious interest groups that has promoted the tuition grants as competition for public schools. Opponents, including teachers unions and civil liberties groups, took heart from the closeness of the vote, saying it showed that diverting taxpayer funds to private and religious schools remains deeply controversial.

U.S. Education Secretary Roderick R. Paige said the vote "takes us one step closer to making the dream of a better education a reality for thousands of children in Washington, D.C." The D.C. provision is the sole surviving piece of a five-city, $ 75 million education choice initiative that President Bush asked Congress to approve last winter.

In 2001, the House rejected a proposal to include vouchers in Bush's No Child Left Behind Act, 273 to 155. In 1997, the Senate approved a D.C. voucher proposal with the knowledge that President Bill Clinton would veto it.

Voucher proponents credited the support the measure has received from some African American parents and political leaders in the District, including Mayor Anthony A. Williams (D), and they used the language of the civil rights movement to describe their goals.

"On the march to educational freedom, D.C. parents are now one step closer to liberation from failing schools," said Virginia Walden-Ford, executive director of D.C. Parents for School Choice, calling vouchers the only hope "for poor, black parents in the District of Columbia."

Rep. Thomas M. Davis III (R-Va.), the House bill's sponsor, said the result would stand despite the razor-thin margin. He claimed that supporters would have votes to spare once lawmakers returned from the weekend. Yesterday, 26 members were absent. "We are breaking the mold in terms of public education for the city," Davis said.

Opponents predicted the plan will face trouble in the Senate and said polls show that most Americans and most District residents are against vouchers.

"We believe that strong bipartisan opposition to D.C. vouchers will ensure this proposal does not become law," said Ralph G. Neas, president of People for the American Way, a liberal advocacy group that says any additional federal funds should be used to raise teacher standards, reduce class sizes and buy more textbooks for all District students.

"What this vote does indicate," said Del. Eleanor Holmes Norton (D-D.C.), "is the one thing we knew all along -- that is, if you want some money from the Congress, you do not tie it to a controversial measure, and nothing is more controversial in the Congress than private school vouchers, in no small part because almost two-thirds of the American people oppose them."

The House legislation directs the Education Department to provide $ 10 million of "opportunity scholarships" next year to students from families earning up to 185 percent of the poverty level, or $ 34,000 for a family of four. The Senate version would fund $ 13 million in vouchers and -- unlike the House bill -- includes $ 26 million for public D.C. charter and regular schools.

Yesterday's House floor debate drew more than 30 lawmakers into a well-worn but intense argument a year after the U.S. Supreme Court upheld the constitutionality of voucher programs by a 5 to 4 vote in an Ohio case. Supporters cited failures of District schools, the flight of wealthy families to the suburbs or private academies and pleas for help from poor parents.

"The fact is, the monopoly of the District of Columbia school system is hurting kids, not helping them. It is time to shake up that monopoly," said Davis, author of the House plan with Reps. John A. Boehner (R-Ohio) and Rodney P. Frelinghuysen (R-N.J.). "This is shock treatment to the public education system. . . . This is a moral imperative."

Opponents said the District program is a stalking horse used by those who oppose public education to impose an unproven idea on an unwilling city and spread it to the states. A majority of D.C. Council and school board members oppose the voucher plan.

Critics argued that private schools receiving vouchers would be unaccountable in spending public funds, and they said the money should instead be used to close a $ 9 billion unfunded obligation for national public education reforms.

"A vote for vouchers anywhere in the country, especially in this economic climate, will be heard and felt throughout the country, especially in your own district," Norton said. "We are not to be your pilot. We are not to be your experiment. You want to experiment? Do it in your own states. Don't do it in the District of Columbia."

Maryland and Virginia lawmakers voted along party lines. Overall, four Democrats crossed the aisle to support the legislation, and 14 Republicans broke party ranks and joined one independent in opposition.

Voters in two states, Florida and Colorado, have approved statewide voucher programs, while state voters have approved pilots in Milwaukee and Cleveland. Since 1972, five other states and the District of Columbia have rejected vouchers and tuition tax credits. The District test came in 1981, when a tax credit proposal failed, 89 percent to 11 percent.

National polls have shown the public split. A District survey by The Washington Post in May 1998 found 56 percent in favor and 36 percent opposed, although differently worded surveys have yielded different results.

News researchers Madonna Anne Lebling and Carmen E. Chapin contributed to this report.