What the Republicans should do to address the problem

This is the best description of Trump's popularity that I think I've seen.  This is a quote from Frank Luntz, a pollster who used to be featured on Fox and now is on CBS (I think).

Mr. Luntz did a focus group with just Trump supporters and said this after the event:

"I want to put the Republican leadership behind this mirror and let them see. They need to wake up. They don't realize how the grassroots have abandoned them. Donald Trump is punishment to a Republican elite that wasn’t listening to their grassroots."

I don't know if I'd use the word punishment but I Mr. Luntz believe correctly points out a key reason - not the only one but a key reason why Trump has the core of popularity that he has in the Republican primary. 

The Republican Leadership has not awaken to the fact that the grassroots have been rebelling against them since 2006.  I have a feeling this election is going to be another message to them.