Many American nations fought wars of independence.
Argentina and Great Britain
UN-United Nations
About 50 nations fought in WW2 but basically the whole world was involved.
Iran
buttholes
Argentina and The United Kingdom.
A civil war is a war fought between the inhabitants of one country, for example, the US Civil War was fought between the South and North US. However, a "normal" war is fought between 2 opposing powers.
The United States fought against the United Nations during World War I and then fought Canada and Emperor Palpatine's droid army after nuking the UN headquarters in New York. The US won.
Platt Amendment Foraker Act
Britain, Australia and Germany.
Woodrow Wilson played a huge role in determining if and when America would get involved in World War I. He also fought for the League of Nations to help avert another World War which won him the 1919 Nobel Peace Prize.