As Brad notes above, Rep. Paul Ryan backed away from his past support for Social Security privatization in the debate Thursday night. But he expressed support for other changes to the program made in his most recent budget. "The kinds of changes we’re talking about for younger people like myself don’t increase the benefits for wealthy people as fast as everybody else," he explained. "Slowly raise the retirement age over time. It wouldn’t get to the age of 70 until the year 2103 according to the actuaries."

That is indeed what Mitt Romney plans to do. He suggests that the retirement age should be "slowly increased to account for increases in longevity." It's a popular proposal, embraced by the Simpson-Bowles plan among others. It's a big cut, 6.6 percent according to Henry Aaron at Brookings. And it reduces benefits across the board, as this chart from the Center for Budget and Policy Priorities shows:

Source: CBPP

 But it's extremely regressive. That's because life expectancy is only going up a significant amount for high earners. People who are lower on the income spectrum are seeing barely any increase:

Source: Economic Policy Institute

So cutting a year of benefits for a poor retiree means much more than cutting a year for high earners. This will also hurt workers in physically intensive jobs more than those with less straining work. A mason who lifts heavy stones all day is likely to have to retire at 62, and take a lower Social Security payment as a result. By contrast, people with mentally engaging and physically non-taxing jobs, such as reporting or think tank work, are likely to want to work well beyond 65. Raising the retirement age won't hurt the latter group as much as the former.