While the polls have been stable so far this year, it’s still only August. The debates and the conventions have yet to occur. Biden only named his running mate yesterday. And the campaign is being conducted amidst a pandemic the likes of which the United States has not seen in more than 100 years, which is also causing an unprecedented and volatile economy.

Nor has it been that uncommon, historically, for polls to shift fairly radically from mid-August until Election Day. Furthermore, there are some reasons to think the election will tighten, and President Trump is likely to have an advantage in a close election because of the Electoral College.

That, in a nutshell, is why the FiveThirtyEight presidential election forecast, which we launched today, still has Trump with a 29 percent chance of winning the Electoral College, despite his current deficit in the polls. This is considerably higher than some other forecasts, which put Trump’s chances at around 10 percent. Biden’s chances are 71 percent in the FiveThirtyEight forecast, conversely.1