American Civil War & Vietnam War.
Undeclared wars: US Civil War, Vietnam War. Declared wars: War of 1812; Mexican War of 1846-1848; Spanish-American War of 1898; WWI; WWII. Just a few examples.
We have engaged in several undeclared wars, such as the undeclared Naval War with France, under President Adams, and the War with the Barbary Pirates under Jefferson. Some of the conflicts, like Korea, were termed Police Actions, not wars. However, Congress did give approval for the use of US troops. Some Indian battles in the west were carried out without a formal declaration against that particular tribe or settlement. Every military action since the end of WWII have been undeclared wars. Korea, Vietnam, Gulf War, Iraq..etc....
World War 1 , two Korean Wars, and the Vietnam conflict are examples of undeclared wars. The US went to war without a Declaration of War from Congress.
Two examples: 1. American Civil War 1861-1865 2. Vietnam War 1961-1975
American Civil War 1861-1865. Vietnam War 1961-1975.
Yes, they happen all the time.
Both were undeclared wars.
The North won and the South lost in both undeclared wars; US Civil War & Vietnam.
There has not been that many; you'll have to settle for two good examples: American Civil War (1861-1865) & Vietnam War (1961-1965)
The opium wars were never signed. Wars are declared or undeclared, not signed.
Undeclared wars
US Civil War & Vietnam War are two examples.