You probably know Social Security and Medicare are huge programs. But do you know how huge?

In Fiscal Year 2011, Social Security cost $731 billion. Medicare–the Federal health insurance program for the nation's seniors–cost $486 billion. Together, the two programs represented 36%–more than a third of all the money the Federal government spends.

Now, Mitt Romney is accusing President Obama of weakening Medicare–the Federal health insurance program for the nation's seniors:

"His $716 billion cut to Medicare to finance Obamacare will both hurt today's seniors, and depress innovation – and jobs – in medicine," Romney said.

Romney would make big changes in Social Security: he'd raise the retirement age…and pay smaller benefits to those with larger incomes. But he would make no change for Americans who are older than 55 right now.

And unlike health care–where he wants states to be in charge–Romney wants Washington to keep running Social Security:

"We have to make it very, very clear that Social Security is a responsibility of the Federal Government, not the state governments, that we're going to have one plan, and we're going to make sure that it's fiscally sound and stable," Romney said.

But President Obama accuses Romney of undercutting Medicare by changing it from guaranteed insurance to a voucher program that may not cover all insurance costs:

"We will reform and strengthen Medicare for the long haul,” the president said, “but we'll do it by reducing the cost of health care – not by asking seniors to pay thousands of dollars more."

As for Social Security, the president says he wants to preserve it, but hasn't been very specific about how he'd do it. We know more about how he wouldn't: he opposes reductions in current benefits, and he's against privatizing the program.

"We will keep the promise of Social Security by taking the responsible steps to strengthen it – not by turning it over to Wall Street."

We all get old, and we all get sick.

And we know, if Medicare and Social Security have serious financial problems, so will many of us.

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