Defensive military alliance, that the US belongs to... ROFLMAO. How long have the NATO countries been at war around the globe? 21 years at least? Or maybe 34 years. Yeah, Iraq war 1, Bosnia, W O terror, and now in a proxy war with Russia. DEFENSIVE alliance that covers the entire globe. We would figure out how to defend China if need be.
A better question is when were we NOT in a war? During the quiet periods you can be sure we were at least plotting coups against governments we didn’t like, or arming and assisting rebel groups. Such is the life of an economic empire.