“If anyone did that in one of our conflicts, it would be considered an act of war.”
Well, don’t forget that both the Soviet Union and China armed North Vietnam and the VC to the teeth, and I don’t remember the U.S. declaring it an act of war by the USSR and the ChiComs.
Sure, but we expanded the war to both Cambodia and Laos to stop the flow of weapons.
I don’t expect the Russians to do anything to us, but they even seem very worried about engaging Poland.