so I don’t see how this makes him more or less likely to do Something Else Evil.

you're right, but it's a matter of how much cooperation he gets and the cultural tone around him - Bush was able to invade Iraq because of 9/11, sometimes political violence really does create a cultural backlash and writes a blank check for retaliation

A brazen political assassination like this might suggest that their opposition might do more than march peacefully in the streets while he dismantles the country.

maybe, but this is exactly the kind of conflict he craves - one fought with guns and blood, it is the preference of authoritarians in power and who desperately wishes to wield the military against his political enemies

The kind of violence that will give pause won't be an assassination that delivers a perfect rhetorical moment to justify the political violence he wants to normalize and bring about.