Shrugging off a barrage of political attacks, House Republicans are on track to hand President Bush a victory this week by upholding his veto of legislation expanding children's health coverage.

To understand why, consider Utah, where Republican Sen. Orrin Hatch is an outspoken supporter of the measure — and the state's two GOP House members oppose it.

Rep. Rob Bishop called the vetoed bill a "dumb idea" for relying on higher tobacco taxes to pay for insuring children, a provision he said would create a need for new smokers.

And Rep. Chris Cannon said that while he agrees with Hatch on one point, they part company on another. "This is a profoundly moral issue," he said in an interview. "But that doesn't mean the government should do it. Government isn't very good at doing some things, mostly because of rigidity."

With a vote set for Thursday, not even Democrats predict they will amass the two-thirds majority needed to override Bush's veto, even on an issue that polls exceptionally well with the public.

While a handful of Democratic lawmakers who opposed the measure are expected to vote to override the veto, not a single Republican has announced plans to switch.

Republicans project confidence.

"We will not see an erosion of our votes," Rep. Eric Cantor of Virginia, a member of the GOP leadership, predicted recently. And as if to underscore the point, Rep. Tim Johnson's office quickly disputed whispered Democratic claims that the Illinois Republican was on the verge of a change in position. "He's voting to sustain the veto," said a spokesman, Phil Bloomer.

The bill originally cleared on a vote of 265-159. If all House members vote on Thursday, supporters will need 290 to prevail, 25 more than they had last month.

For their part, Republicans say they are looking forward to compromise talks after the vote is held, although some express concern that Democrats may spurn Bush's call to negotiate.

"I believe the Democrats fully believe they can exploit this" for political gain, said Rep. Mike Castle, a Delaware Republican who voted for the measure that Bush vetoed.

"This is a hard bill to explain," said Rep. Deborah Pryce of Ohio, another GOP supporter.

But House Republicans quietly distributed a survey by pollster David Winston, who is close to Rep. John Boehner of Ohio, the party leader, with suggested talking points.

It said critics of the legislation can win the public debate if they say they favor "covering uninsured children without expanding government coverage to adults, illegal immigrants and those who already have insurance...." A copy of the poll was obtained by The Associated Press.

Additionally, an AP analysis suggests individual Republicans who side with Bush may have relatively little to fear politically. The 151 Republicans who voted against the bill when it passed last month averaged nearly 64 percent of the vote in their most recent election. Many had vote totals in the 70-percent range, making them all but invulnerable from attack.

Among those who supported the measure, the average vote total in 2006 was 59 percent. While several among them are in safe seats, the list includes well-known moderates as well as those Republicans who squeaked to victory in 2006 such as Rep. Vern Buchanan of Florida and Jon Porter of Nevada; or those with statewide ambitions, including Rep. Heather Wilson of New Mexico and Tom Davis of Virginia.

But the list of opponents of the legislation, too, includes men and women who faced difficult races before, or have been targeted by Democratic allies in the run-up to the vote.

Rep. Peter Roskam, R-Ill., who won his first term last year with less than 50 percent of the vote, said his opposition was consistent with his record in the Illinois Legislature and the campaign he ran last year.

"It's an incremental creep toward socialized medicine in my view," he said of the measure.

American United For Change targeted Florida Rep. Eric Keller, airing an ad that said he and the president "would rather send half-a-trillion (dollars) to Iraq than spend a fraction of that here at home to keep our kids healthy.

"Congress can override Bush's veto. So ask Congressman Keller to think again."

But Keller, in an interview off the House floor, said he's not switching. He said he supports the children's health program, and supports an expansion along different lines.

"I want to be able to provide kids with health insurance first before we provide coverage to adults." He said he opposes the bill's tax increases and argues it would allow coverage for some families with income up to $84,000 — a claim disputed by the measure's sponsors.

Rep. Cliff Stearns, another Floridian, boasted that the ad campaigns have passed him by. "When it comes to tax increases, I'm seen as a lost cause, so the Democrats haven't every bothered to advertise against me," he said.

Rep. John Peterson of Pennsylvania is another target. A solid conservative with a strong anti-abortion record, he faces a televised attack similar to the one waged against Keller, as well as a radio commercial from Catholics United.

"I'm concerned that Congressman John Peterson says he's pro-life, but votes against health care for our children. That's not pro-life, that's not pro-family," says the commercial.

In an interview, Peterson responded that he was instrumental in creating a state insurance program while in the Pennsylvania legislature.

He lists numerous objections to the measure that Bush vetoed. "It's my strong opinion that this bill makes it easier for an illegal alien to get (health) benefits and Medicaid benefits," he said in an interview.

He said the measure eased requirements for prospective Medicaid beneficiaries.