Just in case there could be any doubt about it, the primary point of this post is to insist that this is a really bad idea. It’s certainly ingenious, and highly topical, but considered solely from a perspective of sub-reptilian amorality, it’s still a really bad idea.
For one thing, it’s massively asymmetric, in the wrong way. Assassinate a McKinley, and it pushes things hard to the left. Assassinate a Kennedy, and it pushes things hard to the left. Assassinate pretty much anybody of any public significance, and the result is the same. Leftists are simply better at fantasy counter-factuals and martyrology, so the assassination of a leftist produces an imaginary ultra-leftist of even greater ideological purity (whilst killing a conservative works, or even turns them into a post-mortuary leftist). We all know that if JFK hadn’t been murdered by Texan capitalism we’d be basking in a socialist utopia by now. (There’s a reason why assassination is the preferred tactic of left-wing anarchists and communists, beside the fact these people are demented criminals.)
The reciprocal is even more compelling. Anything that spares leftists from the consequences of participating in reality aids their cause. To consider only the most prominent potential target, Barack Obama alive and in power is the greatest single asset the Outer Right has ever known. Felled by an assassin, he would become the capstone of progressive mythology, and everything he’s aiming to achieve would have turned out absolutely perfectly. If there’s a black counter-assassination market, surreptitiously protecting key agents of the Cathedral from acts of violence, it would be infinitely more effective to invest in that.