If Democrats were heading into a national primary election in late April, journalists would be writing that Bernie Sanders has drastically narrowed Hillary Clinton's lead in the polls.
The good news for Clinton would be that she still holds a lead. The bad news would be that Sanders's ascent, while not strictly relentless, has been fairly steady over time. He started the race a much more obscure figure than Clinton, and over time he keeps gaining on her.
Journalists generally aren't writing this story, because we're not heading for a national primary. Instead, we're more than halfway through a series of state-by-state contests in which Clinton has already built up a very large delegate lead that she is likely to expand in the New York primary this week.
But the national polling isn't irrelevant. So-called superdelegates — party leaders who get an automatic ticket to Philadelphia and who are free to support whoever they want — are party insiders, and therefore are currently overwhelmingly backing Clinton. And because of that, Sanders supporters have directed a fair amount of ire at the whole institution.
Yet Sanders's growing strength in national polling helps explain exactly why they're there. Imagine we wake up on June 8 to find Clinton narrowly ahead of Sanders in pledged delegates but solidly behind him in national opinion polling. Would it really be so crazy for party leaders to decide that current polling is a better reflection of the will of the people than months-old landslide Clinton victories in big states like Texas and Florida?
This kind of thinking is exactly why Clinton herself was so reluctant to concede defeat to Obama during the 2008 primary cycle. And, indeed, in late April and early May she briefly overtook him in national polls, which raised the specter of superdelegate intervention.
Of course, back then Clinton did have two things going for her that Sanders does not. One is that Obama beat her badly in most caucus states, which left the democratic legitimacy of his delegate lead up for question. The other is that even though Obama had a fair amount of establishment support, Clinton was always the more insider-friendly candidate, with natural ties to the superdelegates. Sanders, by contrast, is definitively an insurgent whom superdelegates aren't going to want to help out if they can possibly avoid it.