"If left alone, NATO would have faded away on its own. "

Wrong. NATO should have "faded away on its own" in 1990 when the Soviet Union collapsed and the Warsaw Pact (NATO's counterpart in the East) was dissolved.

The fact that NATO did not "fade away" tells you that it was switched from a "defensive" alliance to an "offensive" alliance.

I mean, in 1991, what was NATO defending itself against? Tell me, please. Because the entire reason for NATO's "defensive" mission had been removed.

I truly look forward to your answer. Please do not disappoint.