the lunatic fringe.
Paul and Huckabee (and probably Walker) have fatally stalled, while Christie and Jindal and Santorum and Gilmore and Graham failed to launch.
Rubio and Fiorina are running for VP.
That leaves the Trump and Carson as the top 2 non-establishment candidates (and top two candidates based on current polling) with Bush and either Walker or Rubio (if he can catch fire soon) as the top 2 (or 3) establishment candidates who are doing a shockingly poor job.
Between the establishment candidates, Bush is sucking the least (which says more about Walker's and Rubio's failure than it implies any success whatsoever by Bush).
Trump and Carson can dominate a 17 candidate field when the vast majority of poll participants aren't paying close attention to the race. Yet after Iowa, New Hampshire, and South Carolina, the field will be down to 3-to-5 candidates and the voters will be paying closer attention. Trump and Carson will lose momentum at this phase (if they haven't lost it before then -- a fate I anticipate for Carson more than Trump), and the establishment will rally around a candidate (probably Jeb!, but maybe Rubio or Walker).
I think we're about 75% likely to see a Bush-Kasich ticket and about 15% likely to see a ticket with Rubio on the top or bottom. A month ago, I'd have put Walker's prospects higher than Rubio's, but this has been a terrible, horrible, no good, very bad month for Walker and I don't think he can recover from this setback.