In 1917, Germany, determined to win its war of attrition against the Allies, announced the resumption of unrestricted warfare in war-zone waters. Three days later, the United States broke diplomatic relations with Germany, and just hours after that the American liner Housatonic was sunk by a German U-boat.
Hawaii. Grover Cleveland was against the United States being an imperialist power and the annexation of Hawaii was something that concerned him.
Answer: The ratification of the Fourteenth Amendment to the United States Constitution
Explanation: