Ron Brownstein asks whether the Democrats' increasingly strident anti-trade line might be a political mistake as well as an economic one (the link expires in a week). Writing from Miami, he notes the signs of international connectedness wherever he looks. Can Democrats plausibly tell their supporters in such places that they would be better off if the US retreated from world markets?

This is the side of the international economic story that Barack Obama and Hillary Rodham Clinton obscured in Ohio with their spiraling denunciations of free trade. But many of America's most vibrant communities are benefiting enormously from their connections to the global economy. What's more, most of these communities, the places that would suffer most if America tried to wall out the rest of world, are becoming Democratic strongholds. This means that in seeking to retreat from globalization, Democrats are threatening the interests of voters and communities increasingly central to their electoral coalition. "The Democrats are in all the globally connected places," says Robert Lang, director of the Metropolitan Institute at Virginia Tech University. "They are biting the hands that feed them."

Lang and his colleagues, in a paper dated March 21, identified the 20 American metropolitan areas most thoroughly integrated into the global economy. The researchers ranked the cities along four dimensions: the presence of global service firms (such as advertising, law, and financial services); whether the area has a major port; whether it has an international airport; and the value of exports that pass through it.

At the top of the list stand New York, Chicago, Los Angeles, San Francisco, and Miami. They are followed by Atlanta, Washington, Boston, Dallas, and Houston. The second 10 start with Seattle and Philadelphia and end with Phoenix and San Jose, Calif.

These globally connected cities retain many differences. But they generally share an expansive outlook marked by receptivity to foreign markets, foreign investment, immigration, and ethnic diversity. "They are the places where when you walk into a building, they have clocks set all around the world," Lang says. In the 1980s, as Hispanic immigration surged, a popular South Florida bumper sticker read, "Will the last American to leave Miami bring the flag?" Today, notes Ojeda, most Miami leaders of all races recognize "that our international [population] base has given us the economy we have."