More democratic regimes would lead to less military aggression and international terrorism. But democracy requires a history of civic traditions that many authoritarians countries do not have! Some countries, after decades of oppressive autocratic rule, are not ready for democracy.
Democracy is needed throughout the world. By helping to guarantee freedom and human rights, democracy can improve the lives of people regardless of their cultural background or religion.
Democracy is universally applicable and must be actively promoted. People who have experienced authoritarian regimes are more receptive to a political process that protects their liberty.