Momentum – Aimee Mann
Nate Silver has called momentum ‘the most overrated concept in elections analysis.’ Perhaps that’s a slight overbid, but only a slight one.
And yet, it’s so tempting! Especially since there actually is some research to suggest that momentum is real and important, particularly in presidential primaries. After all, the whole point of the drawn-out primary process is to allow small shifts in the early stages to guide and inform later events. You cull down the field through momentum effects, where a couple good results causes future undecideds to break in your direction. Or, perhaps more importantly, by encouraging tepid support for second and third tier candidates to melt away.
That said, I wanted to address the question of ‘momentum’ as it relates to Clinton and Sanders. My general bearishness on the Sanders candidacy has incited some pushback from Sanders supporters, with one key point being the trend of the election being in his favor.
The (perfectly fair) argument goes like this: Sanders remains behind by seven-ish points in the Pollster average, which is a big margin, but is a heck of a lot closer than it used to be (it’s worth noting that he’s down by a full 10 points in the 538 poll aggregate, which I think is slightly better than the strict Pollster one). And the trend is clear. Clinton is holding firm, but Sanders is gaining, steadily and emphatically.
Which all means that, to some extent, this is just a battle of expectations. Sanders needs a narrative of growing insurgency, which is building and ready to overwhelm the establishment. If his loss in Nevada is read as a genuine setback, it might risk quelling that spirit and becoming a self-fulfilling prophecy.
So I absolutely get why Sanders supporters want to push back on the narrative of Clinton inevitability.
But from the perspective of an analyst, there’s a big problem with all this: we just haven’t seen any real evidence of voters leaving Clinton. Sanders hasn’t cut into her support in any real way; he’s simply acquired the excess capacity. Yes, there have been ups and downs for her, but her support is right around where it was back in September. It’s possible that Sanders-excitement has inspired new people to join the voting pool, but if that’s happening, then Clinton is picking up additional support to weigh against them.
So, for all that Sanders is doing amazingly well, nothing we’ve seen yet actually suggests that Clinton lacks the voting base necessary to win her the nomination. That is: Sanders’ momentum is currently about hoovering up the half of the electorate that isn’t yet settled on Clinton, and there’s a clear ceiling on that. Of course it’s possible that he’ll change things even more, and really tip the race on its side. But we just haven’t seen anything like that yet.
This particular kind of momentum, where a candidate who appeals more directly to the base gathers up all the disaffected folks who would be willing to settle for the mainstream candidate but aren’t quite ready to get there yet, is pretty well understood. You only have to look back four years to see a perfect example.
Look at this chart and tell me that Candidate B isn’t in great shape. Look at all the momentum!
Except if we go just a couple weeks further down the road, reality sets in quite firmly, and we get this picture:
This is, of course, Romney vs. Santorum. And it’s not hard to see that scenario playing out again.
Is the race completely over? Absolutely not. And it’s a testament to the Sanders campaign and his supporters that it still remains in doubt. But it’s nevertheless true that Clinton remains the prohibitive favorite. The betting markets have her around an 85% chance, and I’d buy at that price. Absent a major shock in the next few weeks, the outcome is pretty settled.