WASHINGTON — Two turbulent months into the launch of the Affordable Care Act's insurance marketplace, President Obama moved to defend the law against Republican attacks Tuesday as the administration tried to deflect attention from the federal website's botched rollout.

The White House's renewed effort to tout the law has two aims: to encourage Americans to sign up for coverage and to reassure nervous Democratic lawmakers and other allies who have watched Obama's so-far unsuccessful efforts to contain the political damage.

With public support for the law sinking steadily and the White House distracted by the disastrous HealthCare.gov website, allies have pushed the White House not to lose sight of another fight: theirs.

Next year's midterm election — much like the 2010 one — will almost certainly be dominated by debate over Obamacare. And much like the last election, that will not be good for Democrats unless the party can find a compelling response to Republicans' call for repeal.

Democratic officials say they've found that message: remind the public why the law was passed three years ago and contrast that with the GOP alternative. Obama previewed the talking point at the White House on Tuesday in an event billed as the launch of the new public relations push.

"We're not going back," Obama said, surrounded by people the White House said had benefited from the law. "You've got good ideas? Bring 'em to me. But we're not repealing it as long as I'm president."

The push is the latest White House attempt to regain control of a debate that since the Oct. 1 debut of HealthCare.gov has been dominated by discussion of website failures, error rates and software fixes.

Republicans, who capitalized on the setbacks, are engaged in their own debate over whether to propose a detailed alternative to Obamacare, or stick with the position preferred by the party's conservative base: repeal the law.

GOP leaders said Tuesday that Americans wanted a "patient-centered" system, not "government-centered." But asked whether the House would ever vote on such a plan, Speaker John A. Boehner (R-Ohio) said only, "We'll see."

The new White House campaign began two days after the administration cautiously declared it had met a self-imposed deadline for getting the site to run smoothly for most users — although Obama stressed Tuesday that more work was needed.

HealthCare.gov is intended to serve 36 states that did not set up their own exchanges. Californians can use their own site, coveredca.com, which has been working reasonably well.

The White House has little choice but to start promoting the federal website and the law's benefits. Consumers must enroll in a plan by Dec. 23 if they want coverage starting Jan. 1. A lag in enrollment, particularly among young and healthy people, will increase the potential for political trouble ahead.

"I need you to spread the word about the law, about its benefits, about its protections, about how folks can sign up," Obama told supporters Tuesday, encouraging them to talk up the still-balky website. "We've learned not to make wild promises about how perfectly smooth it's going to be at all times."

Some of Democrats' political problems are clear. The latest Kaiser Family Foundation poll showed support for the law had dropped significantly among Democrats and major Democratic-leaning voter groups, including young people, women and Latinos.

Support for the law climbed in September and early October, but dropped sharply in November, particularly among Democrats. Support couldn't drop much among Republicans, an overwhelming majority of whom already opposed the law.

In October, 70% of people who identified themselves as Democrats said they had a favorable opinion of the law. But in the poll taken Nov. 13 to 18, that had dropped to 55%. Among women, support had declined to 32% from 40%. Among Latinos, support slid to 44%, down from a high of 54% in September.

Democrats say they can stem the bleeding among those groups with a message that doesn't oversell the law.

"This isn't making an argument that the law is great," said one Democratic operative, speaking anonymously to be candid about the campaign. "This is making the argument that the middle class can't afford the consequences of Republicans repealing the law."

Over the next three weeks leading up to the December enrollment deadline, the White House and Democratic allies will highlight one benefit each day, aiming to remind voters of the most popular elements — each of which would disappear, Democrats say, if the GOP drive for repeal were successful.

For the most part, Republicans met the news of a fresh attempt to sell the 3-year-old Affordable Care Act with mockery, noting that the president had repeatedly zigzagged away from talking about his signature domestic achievement.