Through the aid of brainpower acquired through Operation Paperclip at the tail end of the European theater of World War II, the United States was able to embark on an ambitious program in rocketry. One of the first products of this was the development of rockets capable of holding nuclear warheads. The MGR-1 Honest John was the first such weapon, developed in 1953 as a surface-to-surface missile with a maximum range. Because of their limited range, their potential use was heavily constrained (they could not, for example, threaten Moscow with an immediate strike).