They opposed it because they feared that Wilson had made too many compromises in the Senate to get it passed.
Answer:
It caused the United States and the Soviet Union to declare war on Germany.
Explanation:
Following the Anschluss of Austria to Nazi Germany, in March 1938, the conquest of Czechoslovakia became Hitler's next ambition. The incorporation of the Sudetenland into Germany that began on 1 October 1938 left the rest of Czechoslovakia weak, and it became powerless to resist subsequent occupation.
