As is so common with you, you run away from your own comment when it is proved wrong, and you segue into something only tangentially related, or completely unrelated.
You said that Ronald Reagan never “messed around” in Russia’s backyard. I proved you were wrong (Reagan armed the Afghanis in the 1980s in their war against the Soviet invasion). Then, without even having the maturity to admit you were wrong, you trot out that you “don’t remember” the Soviets ever telling the US to butt out. I can only assume you were either an infant in the 1980s or you were born in the post-Reagan era. That could explain why you “don’t remember,” because you weren’t around then (or, if you were, you were just barely past the embryonic stage of development). Because any sentient being alive back then was aware of the Soviets bitching about the US arming the Afghanis, and resorting to their standard — and toothless
— threats. Reagan saw the Soviets as the blowhard bullies that they were, and he called their bluffs, time and again.
Prove that Afghanistan was a ‘red line’ for Russia. I haven’t heard such, and without that, it’s no different than Vietnam, or El Salvador.