We wouldn’t have McCain if we didn’t let independents and democrats vote in our primary elections. Have only Republicans vote in Republican primaries, and have conservative states go first in the primaries, not Iowa and New Hampshire.
You beat me to it. Close all the primaries to registered Republicans only. McCain is what we get with open primaries. Let the grass roots conservatives, not milquetoast moderates, decide who would be the strongest candidate and the standard bearer.