How about a campaign to move back to closed primaries state-by-state, by referendum if possible?
The establishment Republicans will never move to close the primary after this; its the way they will win this nomination, if that occurs. If Cochran wins by 51 percent, that means that Haley Barbour and his money only needed to buy 2 Democratic voters per 100 to push him over the top, meaning that Democrats will have selected the Republican nominee — something the party “leadership” was (unjustifiably)complaining about 2 weeks ago when Cantor went down to defeat.