Social Security was created in 1935 with a retirement age of 65, but since then life expectancy at that age has increased by about six years, according to the National Center for Health Statistics.
Today the full Social Security benefit retirement age is 66 for people born from 1943 to 1954. It then increases by two months for each birth year (66 years and two months for those born in 1955, 66 and four months for those born in 1956 and so forth), until those born in 1960 or later get full benefits at age 67.
Raising the age eventually to 70 could prove to be politically acceptable because it wouldn't have an immediate social impact, but it would demonstrate that politicians are resolute enough to mend one of the government's most popular social programs and to tackle the national debt.
If they did, they'd have substantial academic backing.
"For a while, there's been a consensus among economists that raising the retirement age makes a lot of sense," said Richard Johnson, a senior fellow and the director of the Retirement Policy Program at the Urban Institute, a Washington research group.
Still, there are potential downsides.
"There are some incredible ramifications to raising the age," said Barbara Kennelly, the president of the National Committee to Preserve Social Security and Medicare. "Not everyone can work until they're 70."
Despite such concerns, the trial balloons are firmly anchored.
Last month, House Majority Leader Steny Hoyer (D., Md.) launched his proposal in a major address to a Washington budget conference.
"We're lying to ourselves and our children if we say we can maintain our current levels of entitlement spending, defense spending, and taxation without bankrupting our country," he said.
"We could and should consider a higher retirement age or one pegged to life span, more progressive Social Security and Medicare benefits, and a stronger safety net for the Americans who need it most."
Soon afterward, House Republican leader John Boehner of Ohio told the Pittsburgh Tribune-Review that the age "eventually" could be raised to 70.
"Raising the retirement age - going out 20 years and not affecting anyone close to retirement, and eventually getting the retirement age to 70 - is a step that needs to be taken," he said.
House Speaker Nancy Pelosi (D., Calif.) would not rule out the option.
Hoyer "made a very important statement about putting everything on the table," she said, "subjecting everything to scrutiny when it comes time to figuring out how we lower the deficit in a very transformational way."
Here's why it's being considered: The federal government faces a historic fiscal crisis. The nonpartisan Congressional Budget Office projects that publicly held debt could reach 62 percent of the gross domestic product by the end of this year, the highest since the Korean War year of 1952. By 2020, the CBO warns, the debt could hit nearly 90 percent of the GDP. History shows that when a nation's debt gets that high, it can cripple the economy.
This month the CBO issued a report suggesting that some adjustments must be made to Social Security's financing. It projected that under the current rules, the system won't be able to pay scheduled benefits starting in 2039.
A bipartisan national commission is considering strategies to reduce the national debt, and the Washington buzz is that everything - even former untouchables such as higher taxes and cuts in Medicare and Social Security benefits - will be considered.