Trying to say you have to turn out your base in greater percentage than the other party. There's a million charts and graphs and they all point to something but I'm still standing on mobilizing your base in greater numbers.
I recall Democratic turnout was lower than Republican in 2016. Might be wrong on that too.
Trump has smartly kept his voters foaming and howling for 3 yrs now. He can count on that base of support to show up.
It will be up to the Democratic machine to turn out it's base in large enough percentage (agreed, where you really have too!).
Clearly, that did not happen in 2016. Recall the Hillary machine was hoping for Trump to win the Republican nomination as they believed he would be easier to beat...
I think the Democrats are at risk of repeating the same mistake in 2020.