Population trends point inexorably toward a more dominant U.S. role in a world that will need us more, not less. For the past several years, the U.N. has published a table ranking the world's 12 most populous countries over time. In 1950, six of the top 12 were developed countries. In 2000, only three were. By 2050, only one developed country will remain -- the United States, still in third place. By then, it will be the only country among the top 12 with a historical commitment to democracy, free markets and civil liberties.
