President Bush heads into only the fourth veto of his presidency with most of America's health establishment and nearly two-thirds of the Congress arrayed against him.

A 12-year-old boy delivered the Democratic response to Mr. Bush's radio address this weekend, and children pulling red wagons are expected to deliver 1 million petitions supporting renewal of the State Children's Health Insurance Program (S-CHIP) to the White House on Monday.

Explaining a vote against healthcare for poor children is not the issue that Republicans wanted to take into the November 2008 elections. Last week, 18 Republicans in the Senate and 45 in the House broke with Bush to support the pending S-CHIP bill, and Democrats say they need to flip only 15 more House Republicans to give the Congress a veto-proof majority.

But the White House and GOP leaders in both houses of Congress say this is a fight worth fighting on policy grounds – and that it may do them some good in spending battles to come and even in next fall's elections.

"Health insurance for poor children is a tall hill for politicians to climb," says Rep. Mike Pence (R) of Indiana, a leading House conservative. "That will make all the other battles that much easier to fight."

A presidential veto of the S-CHIP bill in its current form is "a sure thing," says White House spokesman Tony Fratto. Bush will risk the political fallout because the policy is wrong. He adds, it "doesn't focus on the core population that needs to be served," that is, children in families earning less than 200 percent of the federal poverty level. (For a family of four, that's an annual income of $41,300 or less.)

By stripping out a requirement that S-CHIP cover 95 percent of the neediest children before extending it to higher-income children, Congress is undermining a key intent of the program, Mr. Fratto says. "We think this is a good program, and Congress should keep it focused on what it was intended to do."

The US Department of Health and Human Services estimates that some 794,000 children in these lowest-income families are eligible for S-CHIP and are not currently covered.

Moreover, the S-CHIP bill reaches so far into higher-income groups that it will "shift millions from private insurance to government-supported care," Fratto adds.

Ten states and the District of Columbia now cover children from families with incomes up to three times the poverty level, or $61,950 a year for a family of four. New Jersey has extended eligibility to families earning up to $72,275.

Bush often cites the case of New York, which sought to extend coverage to families earning up to $82,600, or 400 percent of the federal poverty level. Democrats note that Washington rejected that extension, and therefore it's not a valid concern. But "the law is still on their books and [would be] more likely to be accepted" by the terms of the law that Congress is proposing, Fratto says.

For Democrats, the crucial statistic is the number of children to be covered under the new law. "We hope the president will change his mind," says Brendan Daly, a spokesman for House Speaker Nancy Pelosi. "So far, we're short of votes" for an override. But if we come back with another bill, "there are some things we will not compromise, and that's the number of kids: 10 million," he adds.

Democrats and child advocacy groups say that Republicans who back the president in opposing an override of a veto on S-CHIP will face the wrath of voters in the next election. They cite a recent poll by the Republican polling firm Fabrizio, McLaughlin & Associates that found that GOP voters support extending and strengthening the S-CHIP program by a 2-to-1 margin. GOP voters also said, by a 4-to-3 margin, that they were less likely to vote to reelect members of Congress if they oppose the bill.

"Republican voters want Congress and the president to deliver a strong children's health bill, and they are saying they will hold accountable politicians who stand in the way," said Bruce Lesley, president of First Focus, a child-advocacy group in Washington, in a statement.

LAST week, the House and Senate passed a compromise version of the bill that increases funding for the S-CHIP program by $35 billion above existing levels, for a total of $60 billion over the next five years. The bill passed the Senate by a veto-proof 67-to-29 vote. It passed the House by a vote of 265 to 159, short of the 290 needed to override a veto if all 435 House members are present and voting.

But Senate Democrats say they do not expect that Congress will need to compromise with the Bush administration over the level of funding or the terms of eligibility. "It won't be necessary, because there are 25 votes in the House that are potentially getable," says Sen. John Rockefeller (D) of West Virginia, who helped draft the first S-CHIP bill 10 years ago.

House GOP leaders say they are confident of the votes they need to defeat an override of a Bush veto. Rep. Zack Wamp (R) of Tennessee, who has broken with Republican leaders and the White House on issues such as campaign finance in the past, says he's been swamped with requests that he change his "no" vote on S-CHIP. Both US senators from Tennessee supported the bill.

But Representative Wamp says he has no intention of switching his position. "It's a crummy bill that isn't honest as to how it's paid for," he says, citing a budget assumption in the pending legislation that demand for the S-CHIP program will drop sharply in 2013. "There's a trend toward bigger government, and we have to hold the line," he says. "It's going to be a tough vote, but we would not have walked the plank if we weren't sure the president would veto the bill."

Republicans who back Bush are still looking for a concise answer to the issue raised by 12-year-old Graeme Frost. "I don't know why President Bush wants to stop kids who really need help from getting CHIP," Graeme said in the Democratic radio address Saturday. He told listeners that S-CHIP funding helped him recover from a "really bad car accident."