It was not because Serbia invaded a NATO country, if that's what you were asking.
Thought of course you knew that already since you obviously know what the operation was called, a fact basically nobody today knows (without looking it up).
Thought of course you knew that already since you obviously know what the operation was called, a fact basically nobody today knows (without looking it up).
But there is a reason, which curiously enough you neglected to mention. As the other commenter pointed out, it was to stop an active genocide which was being prosecuted by Slobodan Milosevic’s military and paramilitary forces.
Just because they weren't "defending a NATO member" doesn't mean that the operation was "offensive".