Area's Exurbs Watched For Further Party Shifts

In his county, African Americans moving down from Prince George's County have been driving growth. About 68 percent of new residents since 2003 have been black, and most have registered as Democrats, Middleton said.

The impact has been clear: In the September Democratic primary for the U.S. Senate seat, Charles was the only jurisdiction besides majority-black Baltimore and Prince George's to support former NAACP president Kweisi Mfume over the winner, Rep. Benjamin L. Cardin.

But neighboring Calvert and St. Mary's counties have seen the opposite trend. There, new residents are mostly white, many in the upper income levels.

"There, it's getting much tougher to be a Democrat," Middleton said. "The Democrats are being squeezed."

Middleton said he is looking for Democratic gubernatorial nominee Martin O'Malley to be elected and help shift those tides.

"I'm hoping he will work with us to bring the Democratic Party back to the middle," Middleton said.

But like Lang in Virginia, strategists in Maryland believe that county boundaries are an outdated way to look at voting patterns.

"What's happening in Maryland is increasing polarization between the densely populated areas and the not densely populated" ones, said former Democratic secretary of state John Willis, who teaches at the University of Baltimore. "You need to be looking at census tracts" rather than county lines, he said.

Gibson, the Republican Party official, agrees.

"Geographical modeling in the 1980s was very successful," he said. "Democrats turned out the cities, and Republicans turned out the suburbs and rural areas. The reality is that now we're kind of falling away from the geographic political model. Particularly in the last six years, campaigns have tried to focus on the voters, and not just where they live."

Through so-called microtargeting, the party can reach out to the one red household in the mostly blue block of intensely blue Silver Spring, for instance.

"I know our campaign and the party, we make a real effort to try to make a 39 percent Republican district into a 40 percent Republican district," he said.

Over time, he pointed out, even the little victories add up.