By Mary Bruce – ABC News

September 21, 2012 – Appealing to senior voters, President Obama today defended his Medicare and social security policies, and argued his opponents would slash the popular entitlement programs to give tax breaks to the wealthiest Americans.

“There’s a lot of talk about Medicare and Social Security that hasn’t been completely on the level over the last several months,” the president said to an AARP convention via satellite. “Here is what you need to know: I have strengthened Medicare as president.”

“These are bedrock commitments that America makes to its seniors, and I consider those commitments unshakeable,” he said.

The president took a swipe at Mitt Romney’s claim that the 47 percent of the electorate that will vote for Obama are people who are “dependent upon government” and believe they are “victims.”

“Medicare and Social Security are not handouts. You’ve paid into these programs your whole lives,” the president said to applause. “You’ve earned them and as president it’s my job to make sure Medicare and Social Security remain strong for today’s seniors and future generations.”

Obama argued that his signature legislative achievement — “Obamacare” — has extended the financial solvency of Medicare and lowered costs for millions of American seniors.

Citing a new administration study of the Affordable Care Act, Obama claimed the average Medicare recipient will save $5,000 over next 10 years thanks to provisions in the law. He said the measure to close the so-called prescription drug donut hole has saved 5.5 million seniors an average $641 each this year.

The Obama campaign has been attacking Romney and his running mate, Paul Ryan, on the airwaves in key battleground states, including a new TV ad launching today that says the Republicans’ proposed “premium support” plan for Medicare — a voucher-style system — will heap costs on seniors to the tune of $6,400 per year.

“We do have to reform and strengthen Medicare for the long haul, but we’re going to do it by reducing the costs of care — not by asking seniors to pay thousands of dollars more while we’re giving millionaires and billionaires a massive new tax cut,” Obama said.

“The other side’s approach to saving Medicare — and you’ll be hearing about this, I gather, after I speak — is to turn Medicare into a voucher program and essentially transfer those costs onto seniors,” Obama said. “All seniors at some point end up being at the mercy of the insurance companies.”

Ryan, who is appearing at the AARP meeting in person today, was preparing to argue that Obama has already altered Medicare and has failed to address its financial woes for the long-term.

“Our plan keeps the protections that have made Medicare a guaranteed promise for seniors throughout the years. It makes no changes for those in or near retirement,” Ryan said in his prepared remarks.

“Our plan empowers future seniors to choose the coverage that works best for them from a list of plans that are required to offer at least the same level of benefits as traditional Medicare. This financial support system is designed to guarantee that seniors can always afford Medicare coverage — no exceptions. And if a senior wants to choose the traditional Medicare plan, then she will have that right.”