For only the second time since July, a poll tracked by Real Clear Politics shows Donald Trump in second place among Republican voters. Polling from the New York Times and CBS News, completed Sunday, has Ben Carson at 26 percent to Trump's 22.

This doesn't make Carson the go-to front-runner. His 4-point lead is within the margin of error, and this is one poll in a series. (Although we will note that the other poll showing Trump in second place was also recent.)

What's most interesting is to look at the change in the Times/CBS poll since their last one, completed at the beginning of September. At that point, Trump led by four points, meaning an eight-point swing. (In the graph below, dots above the diagonal line are candidates that saw improvement since the last poll; dots beneath are candidates that are doing worse.)

That graph shows the real story of the new poll. You can see it better without the little arrows.

There's Trump. There's Carson. And then way, way, way, way back there, there's everyone else. Sure, Carly Fiorina saw a three-point improvement since September, a 75 percent gain in her poll numbers. But that's a little like congratulating a marathon runner that finishes in six hours for setting a new personal best.

Right now, it is a two-person race. But these things can and will change. The Times article summarizing the poll gets to that: "A majority of Trump supporters, 55 percent, said their minds were made up. But 80 percent of Carson backers said it was too early to say for sure that they would eventually support him." This echoes what we've seen in the past (and what our Jenna Johnson reported this week): Trump's got a hardcore fan base.

One last graph. Back in September, we noted that the margin by which Hillary Clinton led the Democratic field was almost the same as the margin by which Trump led the Republicans, the sort of sentence one never would predict having to type. But that is no longer the case.

For all of this talk about the gap between Trump, Carson and the rest of the Republican field, they're about 17 points in front, according to the RCP polling average. Clinton is up by 23. But at least Bernie Sanders set a new personal best.