Why did Henry James become a British citizen in 1915?

Henry James became a British citizen in 1915 primarily to demonstrate his support for Britain during World War I. His decision was motivated by a desire to throw his moral weight behind the British cause and served as a protest against the United States' initial neutrality in the conflict.12

Following his naturalization, James was honored with the Order of Merit by King George V. He passed away the following year, in February 1916, before the United States eventually entered the war.132