There are likely to be so many bad consequences of this.
Authoritarian despots the world over are going to draw succour from it. And the US has lost still more of any 'moral authority' it had. I bet far-right nutters here in Europe are going to be fired-up by it, maybe some will eventually do something similar. The Trumpist right themselves won't stop here, this is probably just the start. They are going to go on causing trouble all over the US for years to come, almost certainly presenting more danger for vulnerable groups than for the State, especially if they are allowed to retain Trump as a figurehead.
Also, I'm guessing black people across the west, will notice the double-standard in how white conservative folk are treated compared to black people, and that's going to increase alienation and bitterness, everywhere, not just in the US.
The only way to head-off some of those concequences is to come down hard on the perpetrators, including the pot-stirrer-in-chief.