Senator Eliot Shapleigh - El Paso, Texas

WASHINGTON — President Bush vetoed a children’s health measure on Wednesday afternoon, effectively killing Democrats’ hopes of expanding a popular government program aimed at providing insurance to children in lower-income and middle-income families.

“Because the Congress has chosen to send me an essentially identical bill that has the same problems as the flawed bill I previously vetoed, I must veto this legislation, too,” the president said in a statement, reiterating his objections to the proposed expansion of the State Children’s Health Insurance Program, commonly known as S-Chip.

“I continue to stand ready to work with the leaders of the Congress, on a bipartisan basis, to reauthorize the S-Chip program in a way that puts poor children first, moves adults out of a program meant for children, and does not abandon the bipartisan tradition that marked the original enactment of the S-Chip program,” Mr. Bush said. “In the interim, I call on the Congress to extend funding under the current program to ensure no disruption of services to needy children.”

Speaker Nancy Pelosi, Democrat of California, said Wednesday afternoon that an extension of the current S-Chip program would be speeded through the House before the end of the week, and that Democrats would keep trying to win passage of a bill to their liking.

“This is indeed a sad action for him to take, because so many children in our country need access to quality health care,” Ms. Pelosi said at a Capitol news conference. She said the president’s supposed concerns about overspending were illogical because taxes on tobacco would pay for the program’s expansion.

The veto was the seventh of Mr. Bush’s presidency, and the second of the children’s health bill, which Mr. Bush had rejected in a similar form in October. Congress sent an updated version of the legislation to Mr. Bush 10 days ago, and he had until Wednesday to either reject the bill or let it become law.

The veto continues the president’s increasingly contentious battle with Congressional Democrats over spending. On Capitol Hill, lawmakers have been trying to wrap up their annual appropriations work by rolling 11 spending bills into one, but Mr. Bush has threatened to veto the immense measure, and the Democrats’ plans appeared in flux Wednesday afternoon.

If Congress sustains the president’s veto of the children’s health bill, leaders of both parties say they hope to pass a one-year extension of the S-Chip program. Their aim is to include enough money in the measure to maintain current levels of enrollment, estimated at 6.6 million children.

To achieve that goal, the Congressional Budget Office says, Congress would need to provide at least $5.8 billion, $800 million more than the current level of spending. The bill Democrats sent to Mr. Bush would have increased spending by $35 billion, bringing the total to $60 billion over five years, and would have added another four million children to the rolls.

“This Congress failed to send the president legislation that puts children first, and instead they sent for a second time one that would allow adults onto the program, expand to higher incomes, and raise taxes,” said Dana Perino, the White House press secretary.