To be fair, the US has been at war* for over 220 of the years its been in existence, so neither has virtually anybody else.
*Depending on how one defines 'war'. If you want to be technical, the US has declared war five times against 11 different nations: War of 1812, Mexican-American War, Spanish-American War, World War I, and World War II. Obviously, many 'informal wars' have been fought, such as Korea, Vietnam, and Iraq; calling something a 'war' seems to be a way to get support for it, over 'police action' or 'invasion'.