Why Lend-Lease needed Britain to prove it could survive

Could Roosevelt have secured Lend-Lease earlier when Britain warned of its financial position?

Probably not; Congress needed evidence that Britain could remain in the war and use American aid effectively.

Congress was unlikely to pass Lend-Lease simply because Britain reported financial danger in December 1940. A belief that Britain was about to lose would strengthen isolationist objections by making aid appear futile. British resistance instead had to show that Germany could be defeated and that American material support could produce a return. The political opening therefore arrived in early 1941 after Britain had survived and inflicted reverses, rather than at the moment of maximum apparent weakness.