The Neutrality Act
Neutrality Act 1935: Prohibiting the export of "arms, ammunition, and implements of war" from the United States to foreign nations at war and requiring arms manufacturers in the United States to apply for an export license.
Neutrality Act 1937 : United States citizens were forbidden from traveling on belligerent ships, and American merchant ships were prevented from transporting arms to belligerents even if those arms were produced outside of the United States.
Neutrality Act 1936 : Renewed the provisions of 1935 act for another 14 months. It was forbade all loans or credits to belligerent.
Neutrality Act 1939 : Lifted the arms embargo and put all trade with belligerent nations under the terms of "cash-and-carry." The ban on loans remained in effects and American ships were barred from transporting goods to belligerent ports.