Appeasement of Nazi Germany (1938)

Neville Chamberlain's Munich Agreement, which ceded Czechoslovakia's Sudetenland to Hitler in exchange for a promise of "peace for our time," is history's most cited example of failed diplomacy. Within a year, Hitler invaded Poland and World War II began. The decision remains controversial because some historians argue Britain needed the extra year to rearm, while others contend earlier resistance could have stopped Hitler when Germany was still militarily weak.