Just had a very interesting thought: Is it within the power of the CA Republican Party to open up their primary and flood the zone with Hispanic Dems to stop Trump?
Too late for 2016. I'm assuming in 2020 we'll get to see lots more proportionality. Possibly lots more cauci, but perhaps they won't go for that -- in the long run the threat to the Republican establishment comes from socons and libertarians, not Trump types.
And if there is one group that does absolutely terrible in caucuses versus primaries, it is the ones that dominate the activist base.
If the GOP is smart they will go for more primaries. Trying to suppress the inevitable shift driven by demographics within the GOP base will only lead to heads on pikes. They need to run realists who accept the modern reality, quit trying to pretend it is 1980 all over again and map a path that accrues both base support and competitiveness in the general. There is no other way this works.