In 1939, Winston Churchill described the Soviet Union as “a riddle, wrapped in a mystery, inside an enigma.” Were he alive today, Churchill might regard the war in Ukraine as “a quagmire, wrapped in danger, inside a dual paradox.” This dual paradox represents two sides of the same geostrategic coin on which the future outcome of that war rests. One side is how or whether Ukraine and the West will deal with Russia now and whenever the war ends. The other equally daunting side is reciprocity and whether Russia will remain a sanctuary safe from major Ukrainian attack while its...