What war that America has ever fought had the least amount of our sides casualties?
Are you asking about U.S. military casualties, civilian both? What constitutes a “SMALL War”?
The U.S. Military casualties in a true War
Revolutionary War 4,435
War of 1812 6,765
Mexican War 13,283
Spanish-American 2,446
World War One 116,708
World War Two 407,316
Korean War 33,651
Vietnam War 58,168
Persian Gulf War 363
US Casualties (not all “MILITARY”) in less than a War (other actions)
1962 Bay of Pigs Cuba 9
1964 Panama Canal Riots 4
1965-1966 Dominican Republic 59
1983 Grenada 19
1983-1991 El Salvador 20
1984-1989 Honduras 1
1986 Libya 2
1989-1990 Panama 40
1991-1992 Somalia, Op Restore Hope 8
2001-02 Operation Enduring Freedom (Afghanistan) 43
2002 Operation Enduring Freedom (Phillipines) 12