The Growing Blue-State Diaspora

Californians have moved to Colorado and Nevada. Massachusetts natives have moved to New Hampshire. New Yorkers have moved to North Carolina and Virginia — and, of course, have continued moving to Florida.

Over the last few decades, residents of many traditionally liberal states have moved to states that were once more conservative. And this pattern has played an important role in helping the Democratic Party win the last two presidential elections and four of the last six. The growth of the Latino population and the social liberalism of the millennial...