The answer is: spreading democratic institutions to more countries.
many citizens in a dictatorship country did not realize the power that they held as a collective. Prior to Globalization, it is very east for dictators to plant fears into people's mind and make them think that there is no way they can disobey the government.
After globalization, they can see with themselves the power of the people in democratic countries. This make more and more people across the globe became resistant to dictatorship style of government.