They don’t really want him but are re-calibrating to choose the best worst candidate from their point of view. Trump is a guy with evolving views. So why not think you can further evolve those views to your favor?
http://www.nbcnews.com/meet-the-press/video/trump-in-1999-i-am-very-pro-choice-480297539914
You should read his article. It could have been written by any number of Davos billionaires. Every Trumpbot argument is clearly smashed by Trump himself.
http://edition.cnn.com/2013/01/22/business/opinion-donald-trump-europe/
Trump doesn't have any fixed principles, so they think they can lead him around by the nose, or at least cut deals with him.
To Trump supporters this may seem next to impossible, until you consider the fact that he is a narcissist of the highest order. That weakness can be taken advantage of.
The GOPe apparently has not been listening to the snake poem. “Take me in oh tender woman”. They are in for a big surprise when Trump takes office and starts cleaning house. LOL!