 Rawls also attempts to draw empirical support for his stability argument from the literature on the democratic peace. Social scientists have found that historically democracies have tended not to go to war with one another. Rawls explains this by saying that liberal societies are, because of their internal political structures, satisfied. Liberal peoples have no desires for imperial glory, territorial expansion, or to convert others to their religion, and whatever goods and services they need from other countries they can obtain through trade. Liberal peoples, Rawls says, have no reasons to fight aggressive wars, so a genuine peace can endure among them. And since decent peoples are defined as non-aggressive, any decent people can join this liberal peace as well.