Who's talking about a deal? The fact is the Soviets had their grubby little hands all through asia, to the extent it wiped out their military strength and aiding in crushing the soviet union. I say we tell those worried we're there that if it wasn't a problem for the soviets to be there for 10 years, it shouldn't worry anyone until we've been there at least so long.
it's not about worrying Russia, China or whomever, it's about the feelings of Afghan people. US troops can remain for as long as Afghanistan wants them to stay, but NOT longer.