Lately, Barack Obama has been saying that major action is needed to avert what he keeps calling a “crisis” in Social Security — most recently in an interview with The National Journal. Progressives who fought hard and successfully against the Bush administration’s attempt to panic America into privatizing the New Deal’s crown jewel are outraged, and rightly so.

But Mr. Obama’s Social Security mistake was, in fact, exactly what you’d expect from a candidate who promises to transcend partisanship in an age when that’s neither possible nor desirable.

To understand the nature of Mr. Obama’s mistake, you need to know something about the special role of Social Security in American political discourse.

Inside the Beltway, doomsaying about Social Security — declaring that the program as we know it can’t survive the onslaught of retiring baby boomers — is regarded as a sort of badge of seriousness, a way of showing how statesmanlike and tough-minded you are.