So, about the element of truth in the criticism of Biden: Once upon a time, there was a peculiar consensus among media figures and would-be centrists that the long-run cost of entitlement programs was America’s biggest problem, that Social Security in particular was in crisis and that something had to be done, with the solution including benefit cuts.

This consensus wasn’t based on hard thinking; it was about the attitude politicians were expected to display. As I wrote way back in 2007, proclaiming a Social Security crisis requiring cuts was seen as a “badge of seriousness,” a way of showing how statesmanlike and tough-minded you were.

The candidate I was criticizing, by the way — the guy I said had been “played for a sucker” — was a politician named Barack Obama. But Biden was certainly pulled in by that conventional wisdom, too, so it’s not hard to find old quotes in which he suggested possible Social Security cuts in the name of fiscal responsibility.

But that was then. These days, Biden, like many Democrats, is calling for an expansion of Social Security benefits. That doesn’t make his previous statements irrelevant; he should acknowledge that he has changed his position, and his history on the issue is one reason progressives worry that, if elected, he might fritter away his political capital in vain attempts to reach bipartisan compromise. (His role in passing the draconian 2005 bankruptcy bill, which got Elizabeth Warren involved in politics, is another.)