A(n) is a competition between nations to develop and produce new weapons and outmatch one another's war capabilities.

The answer is "arms race".

An arms race, in its unique use, refers to a competition between at least two states to have the best military. The developing threat of the nuclear-arms race has neglected to rouse much verbal confrontation. Atomic arrangement is never again broadly examined in the media; the general population has been enlightened small regarding a subject of existential significance; and inquiries once energetically contended have been to a great extent overlooked.