By Christopher Lee and Jonathan Weisman

A broad House majority gave final approval last night to a $35 billion expansion of the popular children's health insurance program, with members from both parties brushing aside a stern veto threat from President Bush to vote their support, 265 to 159.

The Senate will take up the bill later this week and is expected to send it to the president with a veto-proof, bipartisan majority. But amid furious White House lobbying, even Republican advocates in the House ruefully conceded that they will probably fall short of the 290 votes they will need next week to override the promised veto.

 "I think it's a heavy lift," said Rep. Heather A. Wilson (R-N.M.), a perennial political target of the Democrats who worked hard for the bill's passage yesterday. "The administration has come to this debate very late, and, as a result, they're asking us to take one for the team here."

Last night, 45 Republicans voted for the bill -- more than Republican supporters had expected and a sharp jump from the five who supported the original House version in August. Eight Democrats voted against it.

The compromise package would expand the $5 billion-a-year children's health insurance program by an average of $7 billion a year over the next five years, for total funding of $60 billion over the period. That would be enough to boost the program's enrollment to 10 million, up from 6.6 million, and dramatically reduce the ranks of America's 9 million uninsured children, supporters said.

"What we're hoping to do is to galvanize the support of the American people behind this legislation," said House Speaker Nancy Pelosi (D-Calif.). "The president will find himself alone."

Indeed, the compromise worked out between the House and the Senate has garnered the support of the health insurance industry, AARP, the American Medical Association, governors from both parties and a platoon of children's health advocates.

But Bush and GOP leaders said the measure would push children already covered by private health insurance into publicly financed health care, while creating an "entitlement" whose costs would ultimately outstrip the money raised by the bill's 61-cent increase in the federal tobacco tax.

"The current bill goes too far toward federalizing health care and turns a program meant to help low-income children into one that covers children in some households with incomes of up to $83,000 a year," asserted the White House yesterday, continuing to push Bush's far more modest $5 billion expansion.

Backers of the congressional bill, including conservative Republican Sens. Orrin G. Hatch (Utah) and Charles E. Grassley (Iowa), have said repeatedly that Bush is dead wrong about the $83,000 figure. Only New York has sought to cover children from families with incomes that high, and the administration turned down the request.

But both sides have dug in. Moderate Republicans openly fretted yesterday that the White House had made the House GOP its firewall, to their political detriment. "I'm a little baffled as to why the Bush people picked this issue to fight it out on," said Rep. Ray LaHood (Ill.). "It's very sensitive. It's about kids. Who's against kids' health care?"

Joining LaHood in voting for the bill were several Republican moderates, including Rep. Wayne T. Gilchrest (Md.), as well as GOP conservatives such as Rep. Rick Renzi (Ariz.).

Rep. Chris Van Hollen (Md.), chairman of the Democratic Congressional Campaign Committee, said he will make sure Republicans who oppose the bill pay a political price, and that price could keep growing. Van Hollen said Democrats should keep sending the bill to Bush until he signs it.

The measure would make it very difficult for states to cover children at higher than three times the poverty level, or $51,510 for a family of three, analysts said. About 70 percent of the children who retain or gain coverage under the bill would be from families earning less than twice the poverty level, or $34,340 for a family of three, according to Genevieve M. Kenney, a health policy expert at the Urban Institute, a Washington think tank.

Throughout the day, both sides lobbed rhetorical strikes, each accusing the other of playing politics with children's health. Republicans attacked the bill on multiple fronts, saying it would move the nation toward "socialized medicine," ease access to Medicaid for illegal immigrants, and lavish "pork-barrel" spending on a few lucky states and districts.

"This is a government-run socialized wolf masquerading in the sheep skin of children's health," said Rep. Jeb Hensarling (R-Tex.).

The bill's fine print does raise indigent health-care reimbursements to Tennessee and Hawaii, helps county-operated health facilities in California's VenturaMerced counties, and boosts Michigan's Medicaid subsidies, a provision inserted by House Energy and Commerce Chairman John D. Dingell (D-Mich.).

But Democrats said that such issues could hardly compete with the central goal of the bill. Rep. Rahm Emanuel (Ill.), chairman of the House Democratic Caucus, contrasted Bush's opposition to the bill with the hundreds of billions of dollars the administration has sought to fund the war in Iraq.

"It's about the priorities, and the president has told us his priorities," Emanuel said.

Briefly, there was a human face to the issue on Capitol Hill yesterday when Bonnie Frost, a Baltimore woman whose four children ages 9 to 14 have been enrolled in the program for eight years, appeared at a news conference with one of them, Gemma, 9, to support the bill.

When Gemma and her brother Graeme, 12, suffered traumatic brain injuries in a car accident in 2004, SCHIP made it possible for them to get the medical care that they needed, Frost said.