Final answer:
Roosevelt sought to assist Britain by increasing military aid through the Lend-Lease program and laying the groundwork for postwar cooperation with the Atlantic Charter.
Step-by-step explanation:
President Roosevelt sought to increase support for Britain during World War II in a number of ways. Aside from the assistance with munitions and the peacetime draft, Roosevelt's most significant contribution was the Lend-Lease program, which he proposed in January 1941. The program granted the President authorization to lend, lease, or sell military supplies on credit to any nation deemed vital to the defense of the United States, which at this time notably included Britain.
The understanding that Roosevelt had regarding the postwar world potentially being "empire-free" and envisioning the United States as the primary world power also reflected his ambitions for a strong Anglo-American alliance. It was this vision that underlay the Atlantic Charter, agreed upon with British Prime Minister Winston Churchill, outlining a postwar order based on mutual goals between the United States and Britain, including self-determination and free trade.