The fact that all these candidates have surged and then dropped (or begun to drop) again and that no one is consistently polling above 15 percent shows how unsettled the GOP field is — not surprising such a long way from the actual voting.

What makes Rubio strong isn’t his polling surge, but that he is well-liked across the party apparatus. He pulls in conservatives with his voting record and moderates with his impressive 2010 Senate victory in Florida, a crucial battleground state.

This is all evident in non-horse-race polling. Rubio’s net favorability rating among Republicans is near the top of the field. The gap between Republicans who could see themselves voting for Rubio and those who couldn’t is among the field’s best, according to an average of CBS News surveys conducted this year…