In response to rising tensions in the world, Congress passed the Neutrality Act of 1935 to prevent the United States from becoming embroiled in future wars. These restrictions reflected the general American view in the 1930s that trading with warring nations from 1914 – 1917 had caused the United States to enter World War I. President Franklin D. Roosevelt invoked the act in October after Italy invaded Ethiopia. Congress expanded upon these restrictions in 1936 by prohibiting loans to belligerent nations. In 1937, Congress mandated that nations at war could only purchase goods from the US that were not war-related and had to transport them in their own ships, a policy known as “cash and carry.” These restrictions limited American involvement in the Spanish Civil War (1936–39), which pitted right-wing nationalists, supported by Germany, against left-wing republicans, supported by the Soviet Union.
Source: U.S. Department of State, Publication 1983, Peace and War: United States Foreign Policy, 1931 – 1941 (Washington, D.C.: U.S. Government Printing Office, 1943), p. 265 – 271. https://goo.gl/vGzRCg.
. . . Resolved by the Senate and House of Representatives of the United States of America in Congress assembled, That upon the outbreak or during the progress of war between, or among, two or more foreign states, the President shall proclaim such fact, and it shall thereafter be unlawful to export arms, ammunition, or implements of war from any place in the United States, or possessions of the United States, to any port of such belligerent states, or to any neutral port for transshipment to, or for the use of, a belligerent country.
The President, by proclamation, shall definitely enumerate the arms, ammunition, or implements of war, the export of which is prohibited by this Act.
The President may, from time to time, by proclamation, extend such embargo upon the export of arms, ammunition, or implements of war to other states as and when they may become involved in such war.
Whoever, in violation of any of the provisions of this section, shall export, or attempt to export, or cause to be exported, arms, ammunition, or implements of war from the United States, or any of its possessions, shall be fined not more than $10,000 or imprisoned not more than five years, or both, and the property, vessel, or vehicle containing the same shall be subject to the provisions of sections 1 to 8, inclusive, title 6, chapter 30, of the Act approved June 15, 1917 (40 Stat. 223-225; U. S. C., title 22, sess. 238-245).
. . . SEC. 5. Whenever, during any war in which the United States is neutral, the President shall find that special restrictions placed on the use of the ports and territorial waters of the United States, or of its possessions, by the submarines of a foreign nation will serve to maintain peace between the United States and foreign nations, or to protect the commercial interests of the United States and its citizens, or to promote the security of the United States, and shall make proclamation thereof, it shall thereafter be unlawful for any such submarine to enter a port or the territorial waters of the United States or any of its possessions, or to depart therefrom, except under such conditions and subject to such limitations as the President may prescribe. When, in his judgment, the conditions which have caused him to issue his proclamation have ceased to exist, he shall revoke his proclamation and the provisions of this section shall thereupon cease to apply.
SEC. 6. Whenever, during any war in which the United States is neutral, the President shall find that the maintenance of peace between the United States and foreign nations, or the protection of the lives of citizens of the United States, or the protection of the commercial interests of the United States and its citizens, or the security of the United States requires that the American citizens should refrain from traveling as passengers on the vessels of any belligerent nation, he shall so proclaim, and thereafter no citizen of the United States shall travel on any vessel of any belligerent nation except at his own risk, unless in accordance with such rules and regulations as the President shall prescribe: Provided, however, That the provisions of this section shall not apply to a citizen travelling on the vessel of a belligerent whose voyage was begun in advance of the date of the President’s proclamation, and who had no opportunity to discontinue his voyage after that date: And provided further, That they shall not apply under ninety days after the date of the President’s proclamation to a citizen returning from a foreign country to the United States or to any of its possessions. When, in the President’s judgment, the conditions which have caused him to issue his proclamation have ceased to exist, he shall revoke his proclamation and the provisions of this section shall thereupon cease to apply.
SEC. 7. In every case of the violation of any of the provisions of this Act where a specific penalty is not herein provided, such violator or violators, upon conviction, shall be fined not more than $10,000 or imprisoned not more than five years, or both. . .