Gallup has an analysis of polling results from the last few presidential elections to indicate that marital status is now an important predictor of presidential vote. In their polling over the summer Romney leads Obama by 15 points among married voters while Obama leads Romney by 21 points among not married voters. What Gallup leaves out of their analysis is any information on what percent of their polling each group is. However, if you look back over the exit polls for the past few elections, married voters have been about two-thirds of the electorate.
We can all hypothesize about why single voters might prefer Democrats. Presumably, that demographic includes many younger voters and single mothers who are likely to be Democrats.
In 2008, the split was 66% married to 34% single. McCain led 5 points among marrieds but that couldn't trump Obama's 32 pts among singles.
If we posit a similar marital split in 2012, and it's been about that in recent elections, and if Romney is truly ahead by 15 pts among married and down 21 pts among singles compared to the trouncing that McCain experienced, shouldn't Romney be further ahead of Obama in the polls? Yet Gallup has Romney now down by three (which is down from the seven-point lead Obama had in the bump after the Democratic convention). Does that tell us something is off about Gallup's sample? Assuming that married voters turn out as roughly the same percentage of electorate that they were in recent elections (65% in 2000 and 63% in 2004 and 66% in both 2008 and 2010), it would seem that, if Romney can maintain about a 15% lead among marrieds and cut one-third off of Obama's lead among singles from 2008, that Romney would be set to lead Obama in the popular vote. I'd be interested to know if Gallup's current screen of voters is modeled on a similar turnout among married voters and, if so, what other screen they're using that shows Obama in the lead even as they're showing Romney's significant advantage among marrieds.
Can Obama get reelected if he loses the independent vote?