Rush is part of the GOPe, just look at him having Rubio on to mislead his listeners on the Gang of 8.
And how Rubio is using a Rush quote in TV ads claiming Rubio is from the Reagan mold.
this google search yields all quotes I mentioned.
https://www.google.com/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#q=bush%20said%20he%20will%20win%20without%20the%20base