John McCain will be greeted in New Hampshire by a University of New Hampshire poll showing him three points behind Barack Obama.

McCain's election planners believe that New Hampshire is a must-win for them.

They hope to capitalize on residual tensions between Clinton Democrats and Obama Democrats, and, of course, on McCain's longstanding relationship with Republican-leaning independents in the state. The problem, of course, is that the state is simply becoming more Democratic, as Democrats and liberal independents move in from other parts of the New England. Bill Bishop's The Big Sort, a tome about partisan clustering, points to the rise in straight ticket voting in New Hampshire, which David Broder has noted was partly responsible for the Democrats taking back control of the state legislature. (And mechanically enabled straight ticket voting is banned!)

Partisan intensity among Democrats is hot, but the state's political culture has a funny way of confounding partisanship. Fully 21 percent of voters say that, although they're leaning toward someone, they still could change their minds, and 28 percent say they could still make up their minds.

There's a strong gender gap, with McCain running 20 points ahead of Obama among men and Obama running 20 points ahead of McCain among women. According to the UNH poll, McCain's electoral base here is among Republicans and conservatives and older votes, and voters with high-school terminal degrees. Obama's doing well among secular voters, liberals, Democrats, and younger voters and ideological independents. Geographically, McCain does better the closer one gets to Massachusetts, and Obama does very well on the eastern seaboard (The Seacoast.)

To win here, McCain will have to outperform his national average by at least several points.

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