As both parties haggle over how to avoid going over the “fiscal cliff” on Jan. 1, one of the ideas that has resurfaced is gradually raising the Medicare retirement age. There’s a very clear rationale for doing this, and it may even sound appealing to conservatives. The problem is that once Obamacare is in place, it cannot be done without shifting costs to younger Americans.

The Centers for Disease Control and Prevention estimates that Americans who reach the Medicare retirement age of 65 can be expected to live an additional 19.2 years — about five years, or 34 percent, longer than they did in 1960. Despite this, the retirement age has held steady at 65 since Medicare was created in 1965.