Who will carry Manchester in November?

So if Democratic U.S. Senate candidate Jeanne Shaheen and presidential nominee Barack Obama have equal support among Democrats and women, why is Shaheen polling a couple points better than the man at the top of the ticket?

Here are some subgroups in which Shaheen leads Obama by five percentage points or more, according to September's Granite State Poll from the University of New Hampshire:

• Registered Republicans: Shaheen has 15 percent support here (a fact that must cause John Sununu's campaign some concern); Obama, only 9 percent.
• Self-identified Independents: Shaheen scores 42 percent here, Obama 35 percent.
• But the following numbers get to the heart of the matter, inasmuch as Obama has had problems with these voters all year long:
• Voters without a college degree: Among voters with a high school education and/or some college education, Shaheen carries 46.5 percent of the vote.  Obama: 41 percent. 
• Working-class and middle-class voters: Among those making $75,000 or less, Shaheen holds 57 percent of the vote. Obama? 48 percent. 

Five weeks from now, a key early barometer will be the city of Manchester, which has plenty of these types of voters. 

Four years ago, George W. Bush and John Kerry fought to a virtual tie here, with the president carrying the city by just 170 votes. Kerry carried the state.

Six years ago against Shaheen, Sununu carried the city by almost 2,500 votes (54 percent of the two-party vote) and won the state by a larger-than-expected margin, 51 percent to 47 percent.

Five weeks from now, it's quite plausible that Shaheen could carry the city while Obama fails to do so. Losing Manchester would not be fatal to Obama's chances of carrying the state. The question will be how close he can keep it. 

Dante Scala teaches American politics at the University of New Hampshire and blogs at Graniteprof.