Phillips was an abolitionist activist in Kansas before the war -- like another obscure Civil War colonel, James Montgomery, whose biography I now happen to be writing. Somebody should write a book about Phillips, too. His careers included work as a journalist and a postwar member of Congress. He also served as a lawyer for the Cherokees after the war, and during it they made up most of his Indian Brigade. Those soldiers under his command deserve most of the credit for capturing and holding the Indian Territory for the Union, in the face of great logistical and other difficulties.
On today's date in 1863, for example, Phillips was fending off a Confederate attack near Fort Gibson. And he wound up dying at Fort Gibson in 1893, while conducting business for the Cherokees.