Here’s one of the things I’d be thinking about if I were him and considering running: Typically sitting vice presidents who want their party’s nominations are very strong frontrunners for them. Alben Barkley was the last veep to seek the presidency and lose, back in 1952. Since then four veeps have won their party’s nomination. For much of this presidency, though, Biden has been seen as someone who might be interested in a run but not nearly as strong a primary candidate as Clinton. The party functionaries who help to account for the veep advantage all lined up behind her. So the question Biden ought to be asking himself is: Why hasn’t he been the frontrunner all along? And have the reasons he hasn’t been gone away?