I’ve never heard him promote anybody before a primary. He likes to stay out of the fray. I think that’s a good call. He avoids the garbage should something go wrong regarding his pick.
However, once a Republican is chosen, he would typically support that Republican. My guess is his supporting McCain in ‘08 was painful for him, as it was for many of us.
But by “staying above the fray” isn’t he saying it’s okay for a RINO to be nominated? People have said he trashed Jeb.