Characterizing the invasion of Poland by Germany and the Soviet Union as “governments leading wars against each other” is sloppy revisionism at best. Poland was invaded by occupying powers.
All war is state terror. As the great Sebastian Haffner wrote:
"European history knows two forms of terror. The first is the uncontrollable explosion of bloodlust in a victorious mass uprising. The other is cold, calculated cruelty committed by a victorious state as a demonstration of power and intimidation. The two forms of terror normally correspond to revolution and repression. The first is revolutionary. It justifies itself by the rage and fever of the moment, a temporary madness. The second is repressive. It justifies itself by the preceding revolutionary atrocities."