Charlie Cook, National Journal:
Nationally, the RCP averages put Trump ahead with 29 percent, with Cruz and Rubio neck-and-neck with 21 and 20.3 percent, Carson with 7 percent, and Bush at 4 percent. Obviously there is no national primary, which is what a national poll would test, but the figures serve as a point of reference, giving a rough idea of how things stand in other places before the circus comes to town.
The reason I remain very confident in saying that Trump will not be the nominee is that while he is getting 29 percent or so of the support of Republicans nationally, 100 percent know who he is and are fairly familiar with him. If they aren’t, the odds of them being a primary or caucus voter someplace is almost nonexistent. The 71 percent of Republicans who are not for Donald Trump may well agree with him on immigration or some other issue, and they like his blunt manner, his defiance of political correctness, or his antiestablishment, anti-politician, anti-Washington message. But they are not for him, nor are they likely to move to his column.
Each of the other candidates is less known and defined, and thus has more room for growth. It does not mean that someone for Cruz today is likely to jump sides and move to Bush, Kasich, or Rubio, or that a supporter of one of these three is likely to jump to Cruz. While the poll numbers are a little soft, and while voters don’t necessarily stay in the lanes that analysts put them in, they usually do.
One useful exercise is to total up the shares of support in each of the three ideological lanes. If Cruz is pulling 21 percent and Carson 7.3 percent, as the RCP averages suggest, that means that 28.3 percent of GOP voters are in the conservative lane and 29 percent in Trump’s lane. The sum of Rubio’s 20.3 percent, Kasich’s 4.7 percent, and Bush’s 4 percent is 31 percent. That means the three lanes are separated by fewer than 3 points, an amazingly even balance. Even if you move Carson’s 7 percent into the Trump column—although it’s hard to imagine Carson’s deeply religious, evangelical supporters gravitating to the often-profane and more-secular Trump—that would only get him up to 36.3 percent, still a long way from the nomination.