Last week a major brouhaha broke out in the chattering classes when Gallup reported a ten-point Republican lead in its tracking of the generic House ballot among registered voters, the highest GOP margin on this measure in Gallup history. Republicans immediately started fantasizing about a landslide larger than 1994; Politico published a target list of vulnerable Democratic-held seats that swelled to 75 with another 13 “on the bubble.”

Well, today Gallup published another weekly installment of the generic ballot poll, and lo and behold, the ten-point GOP margin vanished, with the two parties tied at 46 percent. Was there a counter-brouhaha about irrational exuberance among Republicans based on a poll that turned out to be an outlier? No, because earlier today two other major generic House ballot polls appeared utlilizing, for the first time this year, a “likely voter” screen. Among this more rarefied sample of the electorate, NBC/Wall Street Journal showed Republicans up 49-40, while ABC-WaPo showed an even larger 53-40 margin. Both polls showed registered voters more or less tied, just like Gallup did today.

It’s entirely possible that when Gallup switches over to a likely voter model for the generic House ballot poll, its findings will be consistent with those of the other two polls, and all this data will make sense. But for now, at a time when expectations and hype and spin are a big part of political “analysis,” it’s just another day when Democrats couldn’t buy a break.