Just a few weeks ago, liberals mocked conservatives who questioned MSM polls that were  based on samples with implausibly high numbers of Democrats.

One influential polling expert went so far as to compare polling skeptics to 9/11 truthers:

That was before a Pew Research Center poll showed GOP nominee Mitt Romney ahead of President Barack Obama by 4 percentage points among likely voters. Now it is Obama supporters who are crying foul:

The sample in the Pew poll of registered voters was 34R/33D/30I, which seems reasonable.

After screening out respondents who are unlikely to vote, Pew was left with a sample of likely voters that was R+3, according to Chuck Todd. (Update: According to page 14 of this report, the Likely Voter sample was 36R/33D/30I.)

If the sample in the Pew poll is skewed toward Republicans, it probably is not off by much. A month ago, Rasmussen reported a 2-point edge for Republicans in party ID. In Wisconsin’s recall election a few months ago, the partisan breakdown was R+1, according to exit polls. Party ID was tied 35-35 in 2010.

But we’re glad to see liberals acknowledge that polls can be skewed and that it is possible for a sample to over-represent members of one party or the other. Maybe Obama supporters won’t call us insane the next time we question a D+13 sample.

Correction: A previous version of this post described Washington Times columnist Henry D’Andrea as a liberal. We apologize for the error!