What is driving the leftist resistance?

Angelo Codevilla:

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The logic that drives each turn of our revolutionary spiral is Progressive Americans’ inherently insatiable desire to exercise their superiority over those they deem inferior. With Newtonian necessity, each such exercise causes a corresponding and opposite reaction. The logic’s force comes not from the substance of the Progressives’ demands. If that were the case, acquiescing to or compromising with them could cut it short. Rather, it comes from that which moves, changes, and multiplies their demands without end. That is the Progressives’ affirmation of superior worth, to be pursued by exercising dominance: superior identity affirmed via the inferior’s humiliation. It is an inherently endless pursuit.

The logic is rooted in disdain, but not so much of any of the supposed inferiors’ features or habits. If it were, the deplored could change their status by improving. But the Progressives deplore the “deplorables” not to improve them, but to feel good about themselves. Hating people for what they are and because it feels good to hate them, is hate in its unalloyed form.

Hence, in our revolution, as in others, which side first transgressed civility’s canons matters only historically. In our revolution, as in others, truth comes to be what serves to increase fellow partisans’ animus against socio-political opponents, and words to mean neither more nor less than what serves the speaker at any given time.

As Thucydides pointed out, once people cease adhering to “those general laws to which all alike can look for salvation in adversity,” partisan solidarity offers the only immediate hope of safety. And that, in turn, is because “those general laws” are by, of, and for the good of all. Once people no longer see any good common to all, justice for each becomes identical with advantage. The only good or justice that prevails is the good or justice of the stronger. As Plato points out in Book I of The Republic, far from being a rare phenomenon, this is mankind’s default state.

Hence, among us as well, subjection by force is replacing conviction by argument. Here too, as contrasting reactions to events fan antagonisms into consuming flames like a bellows’ blows, victory’s triumphs and defeat’s agonies’ become the only alternatives

Although understanding our revolution’s logic tells us nothing about how it will end, keeping it in mind sheds light on what is happening at any given time.
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There is much more.
 
Codevilla is right that the "resistance" is largely made up of people who look down on those who disagree with them.  It is one of the reasons they have often resorted to mob violence, especially the militant Antifa and other groups who seek to intimidate adversaries rather than debate them on the merits of policies.  I think it is also why they have bought into the Russian collusion hoax and keep pushing it "without evidence."