From NBC's Athena Jones
At a rousing event with affordable health care advocates, President Obama defended the health-care overhaul he signed into law last year, saying it had not killed jobs or hurt seniors and that it was important to helping lower the deficit.

Calling access to quality affordable health care "part of the American dream", the president spelled out the benefits of the new law that are already in effect -- from tax credits for small businesses to insuring children with pre-existing conditions -- and outlined ones set to kick in later and he reiterated his promise to work with anyone, Republicans or Democrats, to improve it.

"I believe that anything can be improved," Obama said at Families USA's 16th Annual Health Action Conference. "I am not willing to just re-fight the battles of the last two years. I'm not open to efforts that will take this law apart without considering the lives and the livelihoods that hang in the balance."

The president's strong defense of a law he spent a great deal of political capital to get passed comes after a vote by House Republicans to repeal the bill. While that effort is certain to die in the Senate and would be vetoed should it ever reach the president's desk, the White House understands the importance of continuing to sell the law and to explain its benefits to an American public that in many ways remains skeptical about it.

During a 20-minute speech that was frequently interrupted by shouting and applause, Obama directly referenced the arguments made by the other side.

"You may have heard once or twice that this is a job-crushing, granny-threatening, budget-busting monstrosity," he said, sparking laughter in the audience gathered into a hotel ballroom. "That just doesn't match up to the reality."

Obama said the economy had grown and added jobs in the 10 months since the law went into effect, more small companies were able to offer their employees coverage and seniors were getting prescription drug help.

"I can report that granny is safe," Obama said, prompting more chuckles.

Repealing the law would raise premiums for the middle class, add costs for large companies who provide coverage to their workforce and put insurance companies back in charge of health care, the president said, adding -- in an effort to address the concerns of voters concerned about the deficit -- that the health care overhaul would slow growth in Medicare and Medicaid costs, two of the biggest contributors to the deficit.

"Repealing this law would add a quarter of a trillion dollars to our deficit over the next decade and another trillion dollars in the decade after that," he said, citing estimates by non-partisan economists and the Congressional Budget Office.

In his brief introduction of the president, the Founding Executive Director of Families USA Ron Pollack thanked him for achieving what presidents had for decades tried to do.

"We're committed to work towards the effective state by state implementation of the Affordable Care Act and we will stand shoulder to shoulder with the president to make sure that no one, absolutely no one takes away from America's families the important benefits and rights of the Affordable Care Act," Pollack told a cheering crowd.