Key marker for Democratic success -- sidewalks

WASHINGTON -- Lots of ways exist to analyze who won what in the 2012 election, but one simple rule of thumb provides many of the answers: If a place has sidewalks, odds are the residents voted Democratic.

President Obama won America’s large metropolitan regions -- the 51 regions in the country with populations over 1 million -- 56% to 42%. Within those regions, he did particularly well in core urban counties, which he won by a huge 55-point margin, according to a new analysis by Ruy Teixeira of the Center for American Progress, a Democratic think tank in Washington. Obama also won large majorities in the inner suburban counties and smaller, but still significant, majorities in the slightly less densely populated counties that lie just outside the nation’s big urban centers.

By contrast, Mitt Romney won heavily in small towns and rural counties that lie entirely outside the nation’s urban regions. The Republican carried small metropolitan areas, defined as regions with populations of less than 250,000, by 12 points and carried rural counties by large margins.

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Unfortunately for the Republicans, just over half the country’s population lives in the large metro areas that Obama dominated while only about a quarter of the nation lives in the small, lightly populated regions where Romney built his biggest majorities.

Some of the most hotly contested territories in recent elections have been the counties that demographers refer to as “emerging suburbs,” places on the edge of large metro regions that have recently turned from farmland into bedroom communities. Romney carried that group overall by a narrow margin, but lost some key emerging counties, including Loudoun County in northern Virginia, which was one of the keys to Obama’s victory in that state.

That same pattern of urban domination, however, hurt Democrats somewhat in congressional elections. Overall, Democratic candidates for the House of Representatives toted up over 1 million more votes than Republicans, but ended up with fewer seats. A big part of the reason is that Democratic voters are more heavily concentrated in densely populated urban districts than are Republican voters. A significant number of Democrats won their seats with majorities of well over 4-1, something that is much less common among Republicans.

As political scientist Daniel Hopkins of Georgetown University noted in a recent blog post, the “Republican House vote is distributed more efficiently across space,” meaning that all other things being equal, Democrats would have to win more than 50% of the congressional votes nationwide to harvest more than half the seats.

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Twitter: @DavidLauter