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

The main purpose of the US passing the Neutrality Act in 1939 on a "cash and carry" basis was to:

limit the spread of Nazi influence while remaining neutral, by selling the British and the French supplies.

Explanation:

In the starting of 1939 (following the Nazi takeover of Czechoslovakia), Roosevelt lobbied Congress to renew the money and carry provision. Roosevelt was ultimately rejected because the provision irreligious and also the obligatory arms embargo remained active.

After the Federal Republic of Germany had invaded the Republic of Poland in Gregorian calendar month of an equivalent year, France and nice the United Kingdom of Great Britain and Northern Ireland declared war on the Nazi regime. In response, Roosevelt invoked the provisions of the Neutrality Acts, however, expressed that the acts might give passive aid to aggressive nations. Roosevelt eventually prevailed over foreign policy supporters and in November the Neutrality Act of 1939 was passed, that allowed arms trade with belligerent nations (only on a money and carry basis) to be enacted. This over the arms embargo and repealed the Neutrality Acts of 1935 and 1937.

American ships and voters were unlawful from getting into war zones (specifically selected by Roosevelt) and also the National Munitions board was chargeable for provision licenses for all arms transactions as specific underneath the Neutrality Act of 1939. Any arms group action that was fortified while not a license carried a penalty of up to 2 years in federal jail.

Limit the spread of Nazi influence while remaining neutral, by selling the British and the French supplies