It's important to understand that Social Security is actually three programs:

• Disability insurance;

• Survivors' insurance, which provides a benefit for minor children of the deceased and some spouses;

• Old age insurance, which provides replacement income, the bulk of Social Security spending.

  All three programs are in financial trouble, in part because fewer workers are paying into the system because of high unemployment, and because there are simply fewer younger workers than in years past. And lots of workers are now taking retirement at age 62, causing a sudden bump in spending.

  The disability insurance fund faces a crisis. It runs out of funds in just three years, largely because hundreds of thousands of people filed for and were granted disability benefits during the recession.

  But covering that shortfall, and the gap in the survivors' fund, is relatively easy, experts believe. Social Security trustees can borrow from the healthier old age fund to pay those benefits.

  Over a longer term, of course, the old age fund will need to replace that cash, along with the surplus it has loaned to the government for other programs. The old age fund is now using interest income as well as tax revenue, allowing full benefits to be paid.

  In 2020, however, the fund will start redeeming the IOUs it holds from the government -- payments the government must make by raising other taxes, cutting other programs, or adding to the deficit.

  And by 2033, those assets will be exhausted, leaving the system unable to meet projected obligations from taxes alone.

  It would still pay some benefits -- roughly 75 cents for every dollar promised.

  But making changes now would extend that date by decades, experts insist.

  "Social Security is a math problem," said Michael Linden of the Center for American Progress.

Democrats

As is the case with Medicare, Democrats have been quite murky when discussing Social Security reform. Last week, former White House adviser David Axelrod was asked about the Obama administration's plans for the program.

"This is not the time," Axelrod replied. "We're not going to have that discussion right now."

Other Social Security advocates have been more forthcoming. A key proposal: Lifting the cap on wages subject to the Social Security tax (known to some as the payroll tax, or FICA).

Under current law, workers pay FICA taxes only on the first $110,100 in wages, making the tax regressive.

"I do think that looking at changing the cap is an important aspect of putting Social Security on a more stable footing," President Barack Obama said last week.

Max Richtman, president of the National Committee to preserve Social Security and Medicare, wants to examine changes in the cap, not -- as some have suggested -- eliminating it all together.

"We want it to be solvent for more than 22 years. We want it to be solvent forever," Richtman said.

His group rejects cutting benefits for wealthier Americans, although reforms put in place in 1983 imposed taxes, for the first time, on some Social Security benefits for wealthier taxpayers.

Democrats also face the ticklish issue of raising workers' FICA taxes, perhaps as soon as next year. Employers already pay a 6.2 percent tax on workers' wages, up to the $110,100 cap, but employees pay just 4.2 percent because of tax cuts passed by Congress to fight the recession.

However, that tax "holiday" ends Dec. 31. Raising it back to the old 6.2 percent level will be politically difficult, but Social Security advocates maintain it's essential to restoring health to the system.

Some groups have proposed raising taxes on employers, but not employees, to cover program shortfalls.

Republicans

The 2012 GOP platform proposes allowing "younger workers the option of creating their own personal investment accounts as supplements to the system."

Workers can already do this, of course, but some Republicans have long suggested allowing workers to divert their FICA taxes into private investments, not just their regular income.

Then-president George W. Bush made private Social Security accounts a centerpiece of his 2005 agenda. It went nowhere, and is even less popular now following the 2008 market collapse.

"When you privatize the system you've really gotten rid of it entirely," argued Michael Linden of the Center for American Progress.

Republican presidential nominee Mitt Romney has not promoted private Social Security accounts. He's said current benefits should remain intact, but that the retirement age should be increased for younger workers. He's also proposed cutting future benefits for wealthier seniors.

David John, a Social Security expert at the conservative Heritage Foundation, has yet another idea: Paying seniors a flat Social Security benefit, rather than one based on income over a worker's lifetime, phased in for workers born after 1985.

"That's equal to about $1,200 a month, in today's dollars," John said. "This allows them to understand what Social Security is going to pay, and then to build extra if they want on top of that."

Still other Republicans have proposed changing the way the cost-of-living is calculated for Social Security benefits. Changing the formula, they argue, will reduce costs by billions over the life of the program.

Path to compromise

The earnings cap will almost certainly be raised, many observers believe, but workers should get ready for a jolt: The FICA tax is likely to go back up, too, as soon as next year.

Pressure also will increase to limit Social Security benefits for higher earning seniors. That will turn Social Security into more of a welfare program, but without such a change the financial pressure grows.

In 1983, facing the imminent collapse of Social Security, a special commission proposed raising the FICA tax, cutting benefits for wealthier seniors, and extending the retirement age. Then-president Ronald Reagan signed the measure, which put the program on solid footing for decades.

Any Social Security compromise is likely to involve a similar all-in approach.

But today's polarized politics makes such a deal much more difficult. Then-congressman Dan Glickman watched as both parties successfully addressed in 1983 what was then called the "third rail" of politics: Touch it, and you're dead.

Could a similar bi-partisan deal be reached today?

"Almost impossible," Glickman said.

In today's political climate, almost impossible gives many advocates some reason for optimism.