The main purpose of the us passing the neutrality act in 1939 on a “cash and carry” basis was to declare war on japan and defeat them quickly before joining the war in europe limit the spread of nazi influence while remaining neutral, by selling the british and the french supplies encourage other countries in central america and south america to send troops to support france allow the us to secretly funnel money in to germany and japan to fund their war efforts – this led to great profit for the us economy