Is There Any Precedent For A Trump Comeback?

Donald Trump now trails Hillary Clinton by 6.6 percentage points, according to our polls-only model. And the clock is ticking. We’re 26 daysfrom the election, and by this point in past campaigns, the concrete had basically dried.

Trump could stage a comeback. It’s possible. But it would be basically unprecedented.

Back in August, after the conventions, I wrote an article saying that while Clinton was a heavy favorite — she led Trump by between 6 and 8 percentage points — the race was far from over. We had plenty of historical examples of races shifting by more than 6 points, even after the political conventions. Since 1952, half of the races for which we had polling after the conventions featured shifts of 5 percentage points or more. Some elections, such as 1968, 1976 and 2000, looked like they could be near or total blowouts, but ended up being rather close.

But look at those same elections now. By this point in those campaigns, the polls had largely settled at a level close to where the elections would end up. And that’s true for pretty much all modern campaigns. Here are polling averages for the week preceding Oct. 12 for elections since 1952, along with the final margin...