By one telling, the tensions and troubles that plague the U.S.-China relationship today can be traced back to the quiet departure of an unmarked C-141 military cargo plane from Andrews Air Force Base, shortly before dawn on a Friday in late June 1989. Less than 20 years after Henry Kissinger faked a stomachache and set off on a secret flight from Pakistan to Beijing that would lay the groundwork for diplomatic normalization after decades of estrangement, Brent Scowcroft was on a secret journey of his own to salvage Kissinger’s legacy.