One thing I've long pondered is that if you're truly an insane extremist lunatic of whatever stripe willing to resort to assassination to change the way the U.S. operates, you have to realize that a Presidential assassination is going to produce a new guy reasonably indistinguishable from the old; assassinating, say, the Speaker of the House or the Senate Majority Leader is going to produce a new guy reasonably indistinguishable from the old; but assassinating a Supreme Court Justice can produce a dramatically different court. I know they've got Federal Marshal protection, but I'd be happier if we really stepped up protection for SCOTUS judges on a par with Presidents as ISTM they're a much more valuable target on some levels. On a related note, I'd also be happier if SOP is that SCOTUS justices get a full autopsy, if only to shut up conspiracy nuts.
Of course, there's very little reason (okay, the pillow is weird) to believe this was relevant with Scalia's death.