Did U.S. Trade with Britain and France Pull America into WWI?

Trade Was Not the Casus Belli

The United States entered World War I in **April 1917** primarily because of **Germany’s unrestricted submarine warfare**, which sank American ships (e.g., *Lusitania*, *Housatonic*) and killed U.S. citizens. While the U.S. traded heavily with the Allies, commerce alone did not trigger entry; the decisive factor was the naval threat to American lives and neutral rights.