As the Iowa Caucuses near and the Republican presidential field enters cage-match mode, there has been some movement in "the three lanes" within the party. To recap, those three lanes are the social conservative lane, the establishment lane and the Donald Trump lane. In short, the latest NBC News/Wall Street Journal poll suggests that the establishment lane is narrowing and Mr. Trump is the biggest beneficiary.
The lanes in the GOP that we have discussed are not solid, stable groupings. They are made up of voters that hold mixed and sometimes contradictory views. There are, for instance, supporters of establishment candidates who have tea party leanings or who also consider themselves to be "values voters."
Here's what seems to be happening in the latest NBC/News Wall Street Journal poll. Voter groups that have supported the GOP's main establishment candidates are beginning to peel off to join other candidates, particularly Mr. Trump.
You can see that peeling away most clearly when you look at changes in support between December and January using the five-way field of Mr. Trump, Texas Sen. Ted Cruz, Florida Sen. Marco Rubio, Former Florida Gov. Jeb Bush and former neurosurgeon Ben Carson. So, Mr. Trump and Mr. Cruz are up and the other three are all down a bit.
But the movement with voter groups within the poll is more dramatic and more telling. Consider the changes among self-described tea party voters.
Again Mr Trump and Mr. Cruz are up a bit in this breakdown, and the other three are down. But when you reorganize those candidates in their proper "lanes" the numbers tell a more striking story.
Between December and January, Mr. Trump saw a five-point increase in support from tea party voters. At the same time, the "establishment lane" saw a five-point decline in tea party support. That suggests that those establishment candidate voters with tea party leanings have decided that they feel more comfortable with Mr. Trump - at least for now.
The social conservative lane, meanwhile, looks more like voters simply moving from Mr. Carson to Mr. Cruz.
The point here is simple. The big lesson out of the 2016 Republican campaign so far is the rise of this "three lane" construction of the party. But the three lanes don't have to be three equal lanes. In fact, in the end they won't be.
The numbers here suggest the establishment lane is being pared down to its most basic set of voters, its core. And regardless of which candidate emerges as the establishment's standard-bearer, he or she is going to have to find a way to widen out that lane again.