The site a party chooses for its convention can say something about the kind of country it wants to build. And when Democrats select where they expect to host Hillary Clinton’s coronation in 2016, they should go to Columbus, Ohio, to show what American cities might yet become. In terms of jobs, urban renewal and a great location at the center of an urbanized state, Columbus has much to recommend it. But it also has other things all too rare in modern American cities: strong leadership and a business community that doesn’t shirk its civic responsibility. It’s a vision of a hopeful future.