To understand first you have to understand the difference between polling and probability. 

Probability tries to predict how likely something is to happen. If polling is 60/40 the person with 40 is going to lose badly, if the probability is 60/40 the person with 40 is going to win almost half the time, flip a coin and it comes up heads four times out of ten is not unlikely. 

Silver ran 80,000 simulations, and in half of them Harris won. Doesn’t mean the votes would be evenly split, it meant her chances were about as good either way. One really high possibility is that polling would be off about 3% either way, and one candidate would run away with the election sweeping every tossup state. The odds of Trump being the one this happened to were a little higher than Harris. 20% of the time.

Why the polling was off 3% I don’t know. The polling has been off for three presidential elections in a row. 3% is certainly not a big error. e 

I’ve smoked enough opium, less euphoria than pharmaceutical opiates, but it takes some work what with mixing in the aspirin, and someone to heat the ball of opium and hold it next to the flame while you draw real slow. Sobriety is an ok thing.