What has a copyright dated 19 August 1919?

The Marine Corps Hymn is the correct answer because it was officially copyrighted on 19 August 1919. This hymn is significant in Marine Corps culture and serves as a symbol of pride and heritage for Marines. It is often played at various ceremonies and events, reinforcing the history and traditions of the Corps.

The other works listed have different histories regarding copyright status and publication dates. The Star-Spangled Banner, which is the national anthem of the United States, has its earliest version from the War of 1812, and its later arrangements were published well before 1919. The Preamble to the Constitution and the Declaration of Independence are foundational documents of the United States, thus not subject to copyright as they are public domain texts created in the 18th century.