no
The US fought Germany and Austria-Hungary in World War I.
Germany, Austria-Hungary, Turkey, and Bulgaria.
Germany and Austria-Hungary
The war declaration of US is from 12 December 1941.
The longest war the United States ever entered was the Vietnam War.
The US battled the central forces, which were Germany and Austria-Hungary.
Germany, Austria-Hungary and the Ottoman Empire
Little War in Hungary happened in 1530.
The last declared US war was WW2.
There is no chance that there will ever be a civil war in the United States.
Yes
Iceland