Any possible ulterior motives aside, bombing a country to democracy ain't gonna work if those countries never had institutions that would support any democratic system imposed on them. It takes time to change a society.
A lesser known fact was America was also partly responsible for the genocide in Cambodia. They conducted bombing raids in Cambodia - a kingdom they were not at war with - to rat out Vietnamese targets. The resulting chaos led to toppling of the monarchy and the rise of Khmer Rouge and we all know what happened next.
America fucked up Libya and Iraq real bad. With Afghanistan at least we are seeing how cruel the Taliban is. Iraq was also oppressive but not to the same degree and can pretty much be ignored if not for the oil. Libya was the saddest one. It's far from being fucked up. It have tourist industry prior to the civil war for example. I still hear people say Gaddafi's mistake was he was not bad enough a dictator. Shouldn't have given the people public education and internet.