1940, Japan abrogated the existing treaty of commerce with the United States. Although this did not lead to an immediate embargo, it meant that the Roosevelt Administration could now restrict the flow of military supplies into Japan and use this as leverage to force Japan to halt its aggression in China. After January 1940, the United States combined a strategy of increasing aid to China through larger credits and the Lend-Lease program with a gradual move towards an embargo on the trade of all militarily useful items with Japan.