IT WAS LATE March 2021, recalled Jake Sullivan, when “we began to see indications of a massive Russian military buildup around Ukraine: the movement of thousands of troops, of tanks, of personnel carriers—armored personnel carriers—and of other sophisticated, advanced weaponry.” No one was quite sure how to read the situation. Putin clearly knew that American satellites would pick up the armored personnel carriers, the missile launchers, and the tent encampments. Troop numbers were increasing every week. None of the buildup was designed to be subtle.
