(3) Democratic Leaders Were Up to the Task
I wrote about the skittishness that I saw in 2016 when approaching GOP leaders about coming out against Trump. These elites realized the inmates had taken over the asylum. And they were either too scared to get in the way of a base they knew was primed to overthrow them, too eager to be the first person to nuzzle up to their new daddy (Hi Chris Christie!), or simply unwilling to use their political capital in such a way that it might benefit someone they hated (translation: Ted Cruz).
Once again, the Democrats did it better.
Democratic party leaders were willing to take on the risk of alienating Sanders and his base for the good of their party. First it was Jim Clyburn who buoyed a shaky Biden ahead of South Carolina. Then Mayor Pete and then Amy Klobuchar bowed out as soon as they were non-viable and eagerly led a 3-day deluge of former foes as they marched to endorse Biden.