John Ikenberry is the Peter Krogh Professor of Geopolitics and Global Justice at Georgetown University.

When the world changed in 1989, America was "deprived of an enemy" as Soviet spokesman Georgy Arbatov expressed it. But that didn't make the prospects for stable, worldwide peace any brighter. What may improve the likelihood of peaceful relations globally is the extent to which nations adopt and perfect democratic practice. America has a national interest in the spread of democracy. It is rooted in its historic values and experience. John Ikenberry explains why this is so.