

Alison Lundergan Grimes. (Photo by Win McNamee/Getty Images)

This is the sort of thing that political junkies love a month before Election Day: A new poll in Kentucky suggesting that a party leader in the Senate rather abruptly trails the challenger he's been trying to fight off (pretty successfully) for months. But it's also time for sober heads to weigh in.

SurveyUSA conducted a poll for several Kentucky media outlets that shows Alison Lundergan Grimes (D) at 46 percent and Senate Minority Leader Mitch McConnell (R-Ky.) at 44 percent. A month ago, the same pollster working for the same outlets suggested that McConnell was up by four. Hence, raised eyebrows.

The margin of error on the polls (full results of which can be found here and here) is about four percentage points. Meaning that the four-point McConnell lead was within the boundary -- and the two-point Grimes lead is even moreso. Which doesn't mean there's nothing interesting to extract from the polls. It just means that the race is close, and that predicting a winner from this moment is like predicting a winner when a Kentucky Derby horse goes ahead by a nose three-fourths of the way into the race. (To use an appropriate analogy.)

Most other recent polls have shown McConnell with a lead, so caution is warranted. Maybe Grimes is surging, just as we perhaps saw the horse a nose-length ahead just as it pulled away. But we need to see what happens a little further down the track to determine that.

That said, there are some interesting nuggets in the new poll. We'll note at the outset that the composition of the two polls is the same -- the same breakdown of Republicans, Democrats, and independents in both the September and October polls. The new poll is a little more heavily weighted to women, but the difference among men is more interesting.

In the September poll, McConnell led among men by 10 points. In the new poll, he leads by one. Even though the new poll is slightly more heavily weighted toward women, that could go a long way toward explaining the six-point fluctuation. More remarkable is a dramatic swing in the 35-to-49-year-old age group. In September, they favored McConnell by 11 points. Now, SurveyUSA has them backing Grimes by 10.

If men really are stepping away from McConnell or if that age group swung wildly against the incumbent, that would suggest something dramatic is happening on the ground -- something that isn't readily apparent from 30,000 feet. But to know that, it's worth waiting just a little bit more time.

That's the problem with polling. It's like watching a horse race where you get to see a flash of the screen every few seconds. Which is why we get understandably get a little to excited when we see something different.