Neutrality, in international law, the state of noninterference and of peaceful relations that one nation maintains with two or more nations at war with each other. The rules of neutrality were established by custom and by several international conferences during the late 19th and early 20th centuries. It has been found almost impossible to maintain many of the traditional rules of neutrality under conditions of modern total war, but no new rules have been accepted.
A neutral nation must be impartial in its conduct toward all belligerents. It must not allow passage through its territory of military forces of one of the belligerents or of war materials already owned by a belligerent. It must not allow recruiting of troops on its territory nor allow any belligerent act on its territory or in its waters. Belligerent troops entering its territory must be interned for the duration of the war. Neutral states may not lend money to a belligerent. They must prevent the fitting out of privateers from their ports and severely limit the duration of visits by belligerent warships.
However, private citizens of a neutral nation are allowed to make loans and ship war materials to a belligerent at their own risk. Their government cannot prevent their property from being confiscated by a belligerent if apprehended for these acts. Nor does a government have to prevent its citizens from crossing its borders to enlist in a foreign army or navy.
Obligations of Belligerents. Belligerents are expected to respect the sovereignty of neutrals and the rights and property of their citizens when they adhere to neutral practice. An enemy's goods are inviolate if traveling under a neutral flag, with the exception of contraband of war. Similarly, a neutral's goods, with the exception of contraband, are not liable to capture when traveling under the enemy's flag.
Belligerents are allowed to board neutral ships to search for contraband goods and proof of destination. Contraband, however, has come to be interpreted by belligerents as being almost anything that is of possible use to the enemy.
Belligerents are also allowed to declare a blockade of enemy ports for the purpose of stopping all commerce to those ports. To be binding, such a blockage must be practically enforceable and not a "paper blockade." Under the "continuous voyage" principle, goods headed for a neutral port may be seized if their ultimate destination is a blockaded enemy port. In practice, belligerents have extended blockades beyond these limitations.
When seized for alleged violation of these restrictions, neutral vessels are impounded until their disposition is decided by the belligerent's prize court. Usually the property is ordered confiscated, and often the neutral objects and claims compensation.
These claims are sometimes settled after the war.
Neutrals insisting on the letter of neutral rights have historically been forced to go to war during any vast and vital conflict. A neutral's geographical location alone may involve it in war; thus Belgium became involved in both World Wars. Nations desiring above all to stay out of war have surrendered some of their actual rights. Pressure brought to bear by belligerents usually compels them to favor the stronger side in order to avoid war.
It has been argued that the League of Nations Covenant and the United Nations Charter made neutrality illegal for their signatories by requiring them to take action against an aggressor. However, the League's assembly declared otherwise and the United Nations' measures during the Korean War left nations considerable freedom to remain neutral.
The United States, as a nation frequently neutral in European wars and engaged in commerce vital to belligerents, has been involved in conflicts over neutral rights throughout its existence. During the Napoleonic Wars, French and particularly British maritime decrees severely harassed United States merchant shipping. The War of 1812 eventually resulted. The United States' interpretation of neutral rights was weakened by its own maritime restrictions aimed at the Confederacy during the Civil War. During World War I, German unrestricted submarine warfare against United States vessels resulted in its entry into the war.
The Neutrality Acts of 1935, 1936, and 1937 were designed to avoid war by embargo provisions restricting the right of private citizens to engage in commerce with belligerents. In order to favor the Allies once World War II began, the Neutrality Act of 1939 eased some restrictions, and by late 1940 the United States was openly aiding Britain.