Seniors Boo and Heckle Ryan at AARP Event

Republican vice presidential candidate Paul Ryan received a chilly reception from a seniors' group on Friday as he argued that popular health and pension programs for U.S. retirees need to be overhauled to ensure their stability.

Members of the retiree group AARP booed and heckled Ryan as he laid out the Republican ticket's case for repealing President Barack Obama's healthcare law and partially privatizing the Medicare health plan.

"I had a feeling there would be mixed reactions," Ryan told the crowd.

The event in New Orleans underscored the gamble that Republican presidential candidate Mitt Romney took on when he picked Ryan as his running mate in August.

And, it came during a tough week for the Romney campaign which has struggled to explain comments the presidential candidate made denigrating people who receive government benefits or pay no federal income taxes — a group that includes those who receive Social Security and Medicare.

As chairman of the House of Representatives Budget Committee, Ryan has led the Republican charge to gradually change Medicare's guarantee of universal coverage into a subsidy that would allow retirees to buy coverage on the private market if they wish.

Ryan and other Republicans argue that private competition is the best way to rein in spiraling health costs, while Obama's Democrats say that approach would force retirees to pay more of their health bills themselves.

"I don't consider this approach bold or particularly courageous. I just think it's a bad idea," Obama told the AARP group less than an hour before Ryan spoke.

So far, Obama seems to be winning the argument. Voters in the 12 most competitive states say they have more faith in Obama than Romney to address Medicare's challenges by a margin of 50 percent to 44 percent, according to a USA Today/Gallup poll.

People over age 65 are more likely to participate in elections than younger groups, and in recent elections they have become one of the most reliably Republican voting blocs. But Romney's 20-point edge among this group has eroded over the past several weeks to the point where the two candidates are effectively tied, according to Reuters/IPSOS polling data.

Still, Obama's landmark 2010 healthcare overhaul has not been popular. Romney and Ryan argue that it could weaken traditional Medicare by squeezing payments to doctors and hospitals, narrowing retirees' treatment options.

Ryan pointed out that Congress has postponed cuts to doctors and hospitals every year since they were passed into law in 1997, and questioned whether the advisory board put in place by Obama's law would have better success.

"Top down bureaucratic cuts to Medicare just don't work. Providers stop providing care — that's what happens," he said.

That argument did not appear to sit well with many in the audience, who booed at several points when Ryan vowed to repeal the law and argued that it would hurt seniors.

Audience members also heckled Ryan over the course of the speech, much of which was met with stony silence. The opposition was not universal, however, as applause mixed in with the boos for much of his appearance.

AARP, formerly known as the American Association of Retired Persons, claims 37 million members and is regarded as one of the most powerful lobbying forces in Washington. It resisted cuts to Social Security and Medicare during budget negotiations and angered many Republicans by working to pass Obama's healthcare law.

Obama appeared to get a friendlier reception from the crowd when he argued that the new law has helped seniors by reducing their out-of-pocket costs for prescription drugs and expanding preventive care options. He pointed out that the Medicare savings in his law extended the program's anticipated solvency by several years.

"Given the conversations that have been out there in the political arena lately, I want to emphasize Medicare and Social Security are not handouts," Obama said. "You've paid into these programs your whole life, you've earned them."

Romney's secretly recorded comments that seemed to write off half the electorate as 'victims,' prompted some Republican commentators to call for an overhaul of the Romney campaign.

Romney's wife, Ann, said they were not helping the cause.

"Stop it. This is hard. You want to try it? Get in the ring," she said on an Iowa radio station late Thursday.