If I might stick an oar in, the entire point of the Cold War was to execute state-sponsored acts of violence by proxy. The wars of “liberation” in Africa alone were and continue to be too numerous to count. The Soviet invasion of Afghanistan and our own covert efforts to oppose it are another example. Vietnam, although that was a case of overt warfare. Korea, same story. Jungle warfare in the Philippines by uniformed units of both sides. Grenada. Berlin. In all of these places there was violent, armed conflict as a direct result of the ideological clash between the United States and the Soviet Union. In my opinion that qualifies as war.
Okay, that’s a argument too. But I don’t accept the war by proxy, only national force versus national force (forces regular or irregular).
I’d say we at war, or too close to differentiate, with Mexico right now too. Because the drug cartels have to be considered as Mexican national forces, albeit irregular.