THE GREAT GALLUP FREAK-OUT…. Two national generic-ballot polls were published within 48 hours of one another — Newsweek showed Democrats and Republicans tied at 45% each, while Gallup showed Republicans leading Democrats by 10, 51% to 41%. Guess which one is causing a massive freak-out in the political world?

Pollsters offered some more glum news for Democrats on Monday night: Republicans have their biggest lead ever on the question of which party voters would support for Congress. Gallup’s “generic ballot” – a staple of election prognostication – shows Republicans with a double-digit advantage.

In the latest Gallup polling, 51 percent of registered voters say they would vote for the GOP candidate in their district if the election were held today; 41 percent say they would support the Democrat. That represents the biggest such lead for the Republicans in Gallup polls back to 1942, and it marks the fourth straight week they have had the edge on the Democrats, who are seeking to retain control of the House and Senate.

I suppose the historic nature of the result — it’s the GOP’s biggest margin since the dawn of time — is fueling interest, while Newsweek‘s even split seems less interesting.

But I’d recommend caution when it comes to the Gallup numbers — not because I’m discouraged by the results, but because the poll itself strikes me as dubious.

Remember, about a month ago, Gallup’s generic-ballot showed Democrats jumping out to an unexpected six-point lead — and I cautioned at the time that overjoyed Dems were almost certainly overreacting to an erratic poll. I have the same concerns now. (And I’d have the same reaction if, a month from now, the same poll showed the GOP’s lead evaporating.)

Looking back over the last several months, Gallup’s generic-ballot has been all over the place, with no real rationale. In April, the GOP built up a big lead, which then disappeared. In late May, the same thing happened. In mid-June, it happened again. Then in July, Democrats built up their biggest lead of the year, only to see it quickly fade. This week, the results have swung back in the GOP’s direction.

The point is, erratic polls with bizarre swings are necessarily suspect. No other pollster is showing these wild fluctuations. Indeed, no other pollster shows Republicans with a double-digit lead. And while we’re at it, it’s worth emphasizing that Gallup’s generic-ballot poll isn’t even a generic-ballot poll in the traditional sense — it’s “aggregated data” from tracking polls.

I’m not suggesting that Dems should just ignore discouraging data — burying one’s head in the sand is never wise. For that matter, even if the political world discounts the Gallup data altogether, it seems overwhelmingly obvious that the GOP has all the momentum with two months left before the midterms. If I had to lay odds, I’d say the smart money is clearly on the GOP taking at least the House.

But I still question the value of Gallup’s results, and think the political world freak-out is an overreaction.

Our ideas can save democracy... But we need your help! Donate Now!

Follow Steve on Twitter @stevebenen. Steve Benen is a producer at MSNBC's The Rachel Maddow Show. He was the principal contributor to the Washington Monthly's Political Animal blog from August 2008 until January 2012.