William A. Galston's and Pietro S. Nivola's Sunday New York Times Magazine article, "Vote Like Thy Neighbor" notes an interesting demographic development that should have significant implications for GOTV campaigns and political advertising:

Our research concludes not only that the ideological differences between the political parties are growing but also that they have become embedded in American society itself...Most strikingly, political polarization has become akin to political segregation. You are less likely to live near someone whose politics differ from your own. It’s well known that fewer states are competitive in presidential races than in decades past. We find similar results at the county level. In 1976, only 27 percent of voters lived in landslide counties where one candidate prevailed by 20 points or more. By 2004, 48 percent of voters lived in such counties.

The authors discuss the reasons for the shift and note that "majorities tend to become supermajorities." They add "When states become more homogeneous, presidential campaigns begin by conceding a large number of contests to the opposition, disheartening their supporters in those states and increasing the majority’s electoral advantage."

Nivola and Galston are OK with the resulting "hard-hitting partisan competition," but lament the ill-effects of growing "hyperpartisanship," which they believe can do damage to "public trust and confidence in government." In his blog at theAtlantic.com, Matthew Yglesias responds to their article, arguing that the more partisanship, the better and he sees "a merited decline in trust" in government, given recent government abuses of civil and human rights. "Why would we pine away for a shift that would make government less accountable but more trusted?," asks Yglesias. A fair question. But distrust of government practices/policies can morph into generalized government-bashing of the sort that enabled the rise of reactionary ideologues like Ronald Reagan and Newt Gingrich and empowered them to do their worst.

In any event, there is not much that can be done about halting the increasing geographic concentration of people with similar political attitudes, short of hoping that better-educated generations to come will lead to more progressive communities everywhere. Until then, Dems should take note of the trend and target their ads and GOTV efforts accordingly.