WASHINGTON — Congress is highly unlikely to repeal the entire 2010 federal health-care law this year. And it's going to be difficult to do it next year, even if Mitt Romney wins the presidency.

Majority Leader Eric Cantor, R-Va., said Thursday that Republicans will try hard to repeal the Affordable Care Act starting with a July 11 repeal vote in the House, where the party holds a huge majority. But Republicans would need 60 votes to move it through the Senate, and 67 to overcome President Obama's certain veto. Republicans have 47 seats in the Senate.

The only faint prospect for repeal would be a strong mandate from the 2012 congressional and presidential elections: a Republican landslide that does not appear on the horizon. Polls suggest the public is not overwhelmingly opposed to the law, and the elections are more likely to be seen as a mandate for economic change, not an overhaul of health-care laws.

Democrats, who provided all the votes to pass the health overhaul in 2010 and lost control of the House in midterm elections later that year, hailed yesterday's Supreme Court ruling upholding the law.

"With this ruling, Americans will benefit from critical patient protections, lower costs for the middle class, more coverage for families, and greater accountability for the insurance industry," said House Minority Leader Nancy Pelosi, D-Calif., who was House speaker when the law passed.

To pass repeal next year, the House would have to remain in Republican hands, and the party probably would need 60 senators.

The odds are staggering. Twenty-three seats controlled by Democrats are up for election this year, compared with only 10 for Republicans. At best, independent analysts see a four- to six-seat Republican gain.

While Republicans may win a Senate majority, the chances the party will gain 13 seats are daunting. No party has had that kind of net gain since 1958.

Republicans' best bet for change is likely to be an effort to dismantle the law piece by piece. They already have tried, and they've picked up dozens of Democratic votes in some cases.

This month, for instance, the House voted 270-146 to repeal a 2.3 percent tax on the sales of medical devices. Thirty-seven Democrats joined 233 Republicans in approving the measure, which is awaiting Senate action that is not expected soon.

More such efforts are expected, particularly next year.

"What you're looking at is a Whac-A-Mole approach rather than full-scale repeal," said Ilisa Halpern Paul, managing government-relations director at the Drinker Biddle & Reath law and lobbying firm.

Congress could try to deny funds for implementing the law, for example, or reconsider the law's Independent Payment Advisory Board, which will be making recommendations about Medicare cuts.

Sen. Tom Harkin, D-Iowa, chairman of the Senate Committee on Health, Education, Labor and Pensions, would not rule out changes in the law. "I've often said that the act is not like the Ten Commandments chiseled in stone. It's like a starter home, suitable for improvement," he said.

But he, like most Democrats, is a strong supporter of the law's major provisions and is likely to resist serious changes.

"It is now in the hands of the American people to determine whether this disastrous law will stand," said House Budget Committee Chairman Paul Ryan, R-Wis.

Presumptive GOP presidential nominee Mitt Romney on Thursday cast the effort to revoke the law as a crusade.

"If you don't want the course that President Obama has put us on, if you want instead a course that the founders envisioned, then join me in this effort," he said in a brief statement. "Help us defeat Obamacare. Help us defeat the liberal agenda that makes government too big, too intrusive, and is killing jobs across this great country."

The crux of the Republican argument is that the health-care law is big government and an enormous tax burden.

But the law also makes profound changes in how many Americans buy and receive health-care coverage. Since it became law in 2010, its provisions have been phased in gradually, a method designed to slowly building support.

Already, children with pre-existing conditions cannot be denied coverage, dependents can remain on parents' policies up to age 26, and millions of Medicare beneficiaries are receiving price breaks on prescription drugs.

Democrats on Thursday tried to move on.

Senate Majority Leader Harry Reid, D-Nev., said: "It's time for Republicans to stop fighting yesterday's battles."