So why do we keep having to remind ourselves to include him in the ‘16 mix? There are two obvious reasons. The first is age: Biden turned 70 last month, meaning that if he runs in the next election, he’ll be 73 during the campaign and 74 on his inauguration – meaning he’d be the oldest person ever to be sworn in as president. (Ronald Reagan didn’t turn 74 until a few weeks after his second inaugural.)

This was enough to create an impression from the moment Biden joined Obama’s ticket in 2008 that V.P. would be his career-capping role, a perception Biden has been trying (to the degree he can while remaining a loyal No. 2) to shake off. The good news for Biden is that age probably isn’t quite the obstacle it used to be. In 1952, for instance, Alben Barkley, Harry Truman’s 74-year-old V.P., believed he was next in line for the Democratic presidential nomination and badly wanted it, only to be bluntly told by party leaders that he was too old. Six decades later, the stigma has probably faded – especially for a septuagenarian like Biden, who has the energy and sharpness of someone many years younger. On the whole, Biden’s age complicates his ’16 ambition but doesn’t by itself kill it.

The other reason Biden is overlooked is more serious: Hillary. The outgoing secretary of state, if she chooses to run, has the potential to be a primary season front-runner like we’ve never before seen.