Personally & IMHO, BT is a solid fella, very patient, comes across as fiscally conservative, though socially....kinda all over the place. If I had to categorize him, I wouldn't go with RINO, I'd go with more or a right leaning moderate. But yes, he was no fan of Romney, instead appeard to actually support a more conservative candidate. Romney comes across as more of an "appeaser", in his efforts to work with both sides, which of course then leads to charges of flip flopping, as he tries to actually get things done.
Now, while I'd want a candidate who's principals are a tad more sound and presumptive, like a Governor Perry or Kasich, what we have is a candidate that appeals to both fiscal conservatives and independents......exactly what's needed to win a national election. Why Bt would be so against him at the outset, well, I'll let him explain that.
Claims that this would be the last Republican President I think are a tad hyperbolic, BUT, that really does depend on a Romney adminstration. Is he going to bring back fiscal sanity, or is he going to be BushIII, placating Democrats by still growing the Government, just not as fast as folks like Obama & Xo would want to. Who he chooses to the Supreme court will also be huge. The 2 latters could indeed disenfranchise many of us conservatives, to the point we might be shopping for a libertarian candidate, in which case the Dems would be running things for quite a long time, until a valid Libertarian 3rd party emerged