I create a typology of technology sharing policies based on the ease and breadth of technology transfer they facilitate and explain choices amongst these policies with an original theory called Threats Over Time Theory (TOTT). TOTT predicts decisionmakers share technology when they face severe threats – to either the survival of their state or the organization that they lead. When such threats exist, decisionmakers adjust the liberalness of their desired technology sharing policy based two factors: the likelihood a future adversary may gain the technology because of the sharing – either through a leak or because recipient itself becomes an adversary – and the speed at which the shared technology is likely to become obsolete. I test TOTT using cases during and between the World Wars – the most recent previous period of multipolar international competition.