Carlos Osorio, File, Associated Press
FILE - In this May 8, 2012 file photo, Republican presidential candidate, former Massachusetts Gov. Mitt Romney speaks in Lansing, Mich.

The headline on the new CBS/New York Times poll is an attention-grabber: Mitt Romney pulls ahead, just in the margin of error. But most importantly, he caught and pulled ahead of President Barack Obama among women.

If accurate, this is startling, as the partisan gender gap is a time-honored facet of U.S. politics: Democrats always do better among women, Republicans among men. Here, Romney actually leads women by two points after lagging by six in last month's poll. It may be that the Life of Julia is less attractive to women than Obama's team supposed.

In addition to the shift in female opinion, shifts to undecided accounted for most of the difference. Romney held steady at 46 percent total, but Obama fell from 46 to 43 percent.

The fact that Obama as the incumbent continues to lag in the mid-40s against a weakened Republican coming out of brutal primary battles does not bode well for November. Conventional wisdom says that elections are referenda on incumbent performance, and this much uncertainty in the electorate creates a lot of upward potential for the challenger.

Another aspect of the CBS/New York Times poll is the gay marriage response. It shows 51 percent opposing gay marriage and just 42 percent supporting. "That 42/51 split on gay marriage is sharply lower than what Gallup found last week. Given Romney’s closing of the gender gap here, support for (same-sex marriage) must also be sharply lower among women (there are no cross tabs by gender), even though most women said they favor gay marriage in Gallup’s poll today," Allahpunit at Hot Air said.

And as the New York Times noted on Tuesday, respondents were skeptical of Obama's motivation in the gay marriage shift, with 67 percent saying it was "mostly for political reasons." Ironically, Obama may have undercut his own ability to exploit cynicism over Romney's similar "evolutions" on social issues.

Beneath the headlines are the details about the polling sample, made up of 36 percent Democrats, 31 percent Republicans and 34 percent independents.

Compare that with a May 3-7 AP poll that showed Obama leading by eight points. That poll had 31 percent Democrats, 22 percent Republicans, 29 percent independents and 17 percent "none of these." That nine-point Democrat advantage differs dramatically from the CBS/New York Times poll.

Weighting is the art buried in the science of polling, used to ensure that the sample actually reflects the known partisan makeup of the population. But balancing that sample comes down to guesswork and hunches and is unquestionably prone to bias.

Whether the differences on female opinion and on gay marriage between this and other polls represents a snapshot of reality or a gross error on the part of the pollsters may never really be known. By the time the voting occurs, the deck will have been shuffled repeatedly.

Eric Schulzke writes on national politics for the Deseret News. He can be contacted at [email protected].