A neutral nation does nothing to assist or impede a belligerent (warring) power.
Neutral nations and belligerents often have different aims. A neutral avoids involvement in the conflict, but usually tries to maintain trading opportunities with the warring parties. Conversely, the belligerent power seeks to defeat its enemy at all costs, including disruption of trade between that opponent and neutral parties.
A series of basic concepts of neutrality has been established by proclamation or international agreement, which may include the following:
- Belligerent ships cannot be built or outfitted in neutral ports
- Belligerent ships may enter neutral ports for repairs and other emergencies, but are subject to internment after a specified time
- Belligerents have the right to search for war matériel (whose definition has been widely disputed) on neutral shipping during time of war, but cannot deny the right of trade among neutrals
- Belligerents may formally declare the blockade of opponents’ ports and deny neutrals entry to those ports
- Belligerent armies are not to enter or engage in hostilities in a neutral nation and are subject to internment if they do so.
Major neutral rights issues involving the United States have included:
- George Washington’s 1793 Proclamation of Neutrality in the face of European war following the French Revolution; the Citizen Genêt affair
- The threats to American shipping from France and Britain in the 1790s, which culminated in the Quasi War with France
- The Impressment issue and the Chesapeake affair during the administrations of Thomas Jefferson
- The British violation of neutral rights in the Alabama affair during the Civil War
- The violation of American neutral rights, not only by German submarine warfare, but also by France and Britain in the years before World War I
- The efforts of Congress to prevent American participation in another world conflict by enacting neutrality legislation during the 1930s
- American violation of German neutral rights by the destroyers-for-bases deal and the Lend-Lease program prior to entrance into World War II.