«since primary mechanics are determined by individual parties and not by law» That's not entirely true. (politics.stackexchange.com)
Unsurprisingly, Deadpool's primary mechanic involves wanton murder — he is an assassin, after all. (giantbomb.com)
To an extent, it is possible; but only assuming that you also get rid of per - state primaries and make primaries popular vote by entire country (which is, in practical sense, impossible, since primary mechanics are determined by individual parties and not by law). (politics.stackexchange.com)