Because the Republicans have a built-in advantage in the Electoral College, a Democratic presidential candidate has to be several points ahead in a national poll to even think about being level, in terms of electoral votes, which are the only things that really count in a presidential race.

I’d like this to be true, but remember that these national polls are not helpful to predict the electoral college. Unfortunately, Trump comfortably leads in many must-win states for Biden. Polls are usually wrong, but it’s the best information we’ve got.

Or he could be leading by 4 points.

Edit: 3 points. I guess I struggle with addition now D:

If you’re leading by 1.5 points with a margin of error of 2 points, then it’s most likely that your lead is real. The range of error is a bell curve. It’s more likely for a well-conducted poll to be off by 0.5 points than 1.5.