From March 1889 to August 1891, he was Professor of Military Science and Tactics at
Louisiana State University. He was stationed in
Alaska when the
Spanish–American War broke out in April 1898. McCain sailed with his regiment to the
Philippines in May, and was present for the
Battle of Manila. He served as the acting assistant adjutant general for U.S. forces in the Philippines, but had to return to the United States in September due to illness. He held various staff positions in the Department of the Columbia and was promoted to
captain in March 1899. In June 1920, McCain reverted to his permanent peacetime rank of colonel and served as adjutant of the
Sixth Corps Area until his retirement in July 1921. He served as governor of the
United States Soldiers' Home in Washington, D.C. from May 1927 to April 1936. He died in Washington on July 25, 1941, shortly before the United States was to enter
World War II, and is buried in
Arlington National Cemetery. ==Awards and honors==