"Where are our plans for a New Deal or a Great Society?" asked Edward W. Brooke, the legendary Massachusetts Republican.

It's not a question anyone in today's Republican Party would dare get caught even considering, but Brooke had the temerity to raise it in The Challenge of Change, a book published in 1966, the year he became the first African American elected to the United States Senate since Reconstruction.

The midterm election that year was very good for Republicans in general, including a Californian named Ronald Reagan. But it was an especially fine year for moderate and progressive Republicans of the Brooke stripe across the Northeast. Their prizes included governorships in Massachusetts, Rhode Island, New York, and Pennsylvania.

In 2010, Republicans run away in horror at the prospect of being called moderate, let alone progressive, and that is an obstacle in the GOP's path to a congressional majority. It will be very hard for Republicans to take the House if they don't break the Democrats' power in the Northeast—and they still have to prove they can do that.

"When we do retain the majority," said Rep. Dan Maffei, a hopeful forty-two-year-old freshman Democrat from upstate New York, "people are going to look at the map and see that the Northeast held."

In 2006, Maffei ran and lost narrowly in what had been in a Republican-leaning district. He then won handily in 2008. Like most freshman and sophomore Democrats, he assumed this year would not be kind to his party, so he's been campaigning hard ever since. The result: Absent a Republican wave of historic proportions, his seat now seems out of the GOP's reach.

Maffei's situation illustrates the extent to which this election is playing out very differently in different parts of the country, a fact often lost in the sweeping commentaries.

A Pew Research Center survey released last week underscored stark regional disparities that could shape the outcome. The survey found that while Democrats trail Republicans by 3 points among all registered voters in the South, they are ahead of the GOP by nine points in the Northeast.

Because of the enthusiasm gap, Republicans do better among those who now seem most likely to vote. Yet the regional variations are even more pronounced in this group: While Republicans are ahead by one point among likely voters in the Northeast, they lead by 15 points in the South. Almost all of the divergence is driven by white voters: Among white likely voters in the Northeast, Republicans have a 10-point lead; in the South, their lead is 35 points.

The emergence of the Northeast as a potential Democratic firewall has been a long time in the making. The steady realignment of the South toward the Republicans, which rendered the party increasingly conservative, called forth a counter-realignment among moderates in the North.

That trend has been accelerating. Since 2006, Democrats have taken eighteen Northeastern seats away from the Republicans, and the impact of this change is especially stark in New England. Among the region's twenty-two House members, not one is Republican. By contrast, nine of the twenty-five House members elected in that 1966 election were Republicans.

This year, Republicans have plausible chances for both of New Hampshire's House seats, and for an open seat in Massachusetts. They also have realistic prospects in a number of formerly Republican seats in New York and Pennsylvania.

But Maffei believes the Republicans' increasingly right-wing image, shaped in part by tea-party activists, will impede the GOP's regional comeback efforts.

"I was often asked in both my races if this district had shifted left," Maffei says of an area that runs from Syracuse to the Rochester suburbs. "I always said, no, the district hasn't shifted, it's still a moderate district. What's shifted is the national Republican Party. I still have local Republicans who are moderate—and I work with them all the time."

The Republicans' new "Pledge to America" released last week avoided specifics that might turn off voters. Yet its tea party–inspired language and its failure to grapple with the budget deficit in any detail make it a document unlikely to win back moderates the party needs.

The GOP still hopes the generalized discontent that allowed Scott Brown to win a Massachusetts Senate seat and shock the nation will be enough to secure it the Northeastern victories it requires. But if expectations are overturned again—this time by a disappointing Republican showing—the region of Brown and Ed Brooke will once again play a starring role. 

(c) 2010, Washington Post Writers Group