It’s tempting to write this story in the form of narrative fiction: “On a frigid early December morning in Washington, the Supreme Court ruled 5-4 that disputed mail ballots in Pennsylvania—” You know, that kind of thing. But given the stakes in this election, I think it’s important to be prosaic and sober-minded instead.
So let’s state a few basic facts: The reasons that President Trump’s chances in our forecast are about 10 percent and not zero:
- As in 2016, Trump could potentially benefit from the Electoral College. Projected margins in the tipping-point states are considerably tighter than the margins in the national popular vote.
- More specifically, Joe Biden’s lead in Pennsylvania — the most likely tipping-point state, according to our forecast — is solid but not spectacular: about 5 points in our polling average.
- Without Pennsylvania, Biden does have some paths to victory, but there’s no one alternative state he can feel especially secure about.
- While a lot of theories about why Trump can win (e.g., those about “shy” Trump voters) are probably wrong, systematic polling errors do occur, and it’s hard to predict them ahead of time or to anticipate the reasons in advance.
- There is some chance that Trump could “win” illegitimately. To a large extent, these scenarios are beyond the scope of our forecast.
- There’s also some chance of a recount (about 4 percent) or an Electoral College tie (around 0.5 percent), according to our forecast.
Before we proceed further, a short philosophical note. I hate it when people use phrases — to be fair, we often use phrases like these ourselves! — such as “Nate Silver is giving Biden a 90 percent chance” or “FiveThirtyEight still gives Trump a 10 percent chance.” We aren’t giving anybody anything. Instead, as former FiveThirtyEight politics host Jody Avrigan puts it, what we’re doing is “mapping uncertainty.” In other words, if Biden leads by about 9 points in national polls, 8 points in Wisconsin, 5 points in Pennsylvania, 2 points in Florida, etc., how does that translate into a probability of victory? That’s what our model is trying to figure out.