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: