The German policy of unrestricted submarine warfare against shipping. This led to the sinking of the Lusitania in 1915. Great Britain and France were major trading partners.
Un-restricted submarine warfare
The Second Great War aka World War 2
Vietnam.
Warmongers, dawg
1964-1975
No, it was a European war we chose to become involved in.
The US got involved in the war on: April 6, 1917.
The Korean War ,
The Korean War/conflict .
The sinking of the Lusitania caused the US to get involved.
The Cold War, then Vietnam.
Pearl Harbor attack