 The "Malenkov-Khrushchev nuclear doctrine" involved the adoption of geopolitical and military challenges to the United States and the participation of the USSR in the nuclear race but "in a distinctly asymmetrical style".The technical manifestation of this undocumented doctrine was the research-and-development of nuclear weapons and their means of delivery; the former large enough to completely (or nearly) wipe out large cities and entire urbanized regions in one strike (i.e.with a single payload and a single aircraft).