" Integrating the military and diplomatic track is essential for success. . . . Nixon and Kissinger encountered this problem, and were defeated by it; when they began negotiating with Hanoi in 1969 there were 550,000 American troops in Vietnam, but under domestic pressure, Nixon unilaterally drew down to about 135,000 while Kissinger negotiated for almost five years. By the time they cut the final deal in later 1973, the two men were like the losers in a strip poker game, naked. They had no chips—or clothes—left with which to bargain; the result was a communist takeover of our South Vietnamese ally less than two years later. Roughly the same thing happened to the Soviets in Afghanistan, without even the negotiating. "
― Steve Coll , Directorate S: The C.I.A. and America's Secret Wars in Afghanistan and Pakistan, 2001-2016