Truthfully, court packing should be electoral suicide for anyone that entertains the notion. It's easy to see why nobody should attempt it: simply put, there's nothing to stop the opposing party from adding even more justices when they come into power, then the original party from doing the same, and so on. But the Dems' base has become so rabid and short-sighted that they're demanding it, and Joe is too senile or dumb to quash the notion outright. Hell, not only did he not stamp out any rumors of court packing, as you pointed out, he's flat-out stated that the public doesn't deserve to know his stance! How the fuck does anyone think this is a good thing to say?
