(CNN)We've learned the lesson multiple times in the last few decades: There is no national presidential election. Candidates can get fewer votes and win, if they win enough states containing a majority of electoral votes. That's something President Donald Trump may hope happens again, because the national polls have had him trailing all year.
The problem for Trump is there's basically no chance he pulls off what he did last time if where he stands now in the national polls holds through Election Day.
If you applied that 2.9-point difference to either the ABC News/Washington Post or Monmouth polls, Biden would be ahead by 7 or 8 points in the tipping point state. He would, in other words, be well ahead in the state that would determine the Electoral College winner.
So what does this mean for 2020? Obviously, a similar national vote from 2016 could produce a similar Electoral College outcome. Even a 5-point national win for Biden wouldn't be "safe." That's because if you were to create a 95% confidence interval in the difference between the national vote margin and tipping-point state margin, it would be 5 points. Anything less and it's a "within the margin of error" situation, even if the national polling were perfectly accurate in showing Biden ahead. You'd really need to look at the state polling closely in such a situation.
Biden's advantage this entire year in the national polling has been north of 5 points, though close enough to that mark for Biden to be at least a little scared.
For Trump to win in the fall, one of three things needs to happen.
The easiest is for Trump to close the gap between Biden and himself nationally. He can certainly do that. We're five months from the election, and races can shift around.
Otherwise, Trump will need a national polling error significantly larger than 2016 and/or the gap between the Electoral College and the popular vote to be significantly greater than the historical average.
These latter two seem like bad bets.