Considering how frequently we put our weapons of war to use ruining the lives of poor people around the world I would say that theory has been disproved. The US is virtually always at war.
What do people think happens if the US withdraws from the global theater and doesn’t maintain its military capabilities? Do we really think that Russia or China would settle for regional skirmishes, and the world would be at peace? The US is very often at war, but there are greater evils than the US bombing ISIS even with the commensurate civilian casualties (hint: few other military powers are so scrupulous about civilian casualties).
You might want to research the contacts, support, decisions and occurrences regarding the US administration and ISIS. And that's just regarding an organization you mentioned. We would lose count if we started listing the countries the US willingly destroyed in cold blood.
