White's studies at Georgetown were interrupted by the Civil War. He enlisted in the
Confederate States Army and served under General
Richard Taylor, eventually attaining the rank of
lieutenant. An apocryphal account states that White was almost captured by
Union troops near Bayou Lafourche in October 1862, but that he evaded capture by hiding beneath hay in a barn. It is possible that White enlisted in the Lafourche Parish militia, as its muster rolls are not complete. There is no documentation, however, that White served in any Confederate volunteer unit or militia unit engaged in campaigns in the Lafourche area. Another account suggests that he was assigned as an aide to Confederate General
William Beall and accompanied him to
Port Hudson, Louisiana, which was besieged and captured by Union troops in 1863. White's presence at Port Hudson, when he was 18 years old, is supported by a secondhand account of a postwar dinner conversation he had with Senator
Knute Nelson of Minnesota, a Union veteran of Port Hudson, and another recounted by Admiral
George Dewey (then a Federal naval officer at Port Hudson), in both of which White referred to being part of the besieged forces. But White's name does not appear on any list of prisoners captured at Port Hudson. According to another account of questionable reliability, White was supposedly sent to a
Mississippi prisoner of war camp. As practically all Confederate soldiers of enlisted rank of the Port Hudson garrison were paroled, and officers sent to prison in New Orleans and later to
Johnson's Island, Ohio, this account is likely not true. When White was paroled, he supposedly returned to the family plantation to find it abandoned, the canefields barren, and the place nearly empty of most of its former slaves. The only documented evidence of White's Confederate service consists of an account of his capture on March 12, 1865, in an action in
Morganza in
Pointe Coupee Parish, which is contained in the
Official Records of the American Civil War, and his service records in the
National Archives, noting his subsequent imprisonment in New Orleans and parole in April 1865. These records confirm his service as a lieutenant in Captain W. B. Barrow's company of a Louisiana cavalry regiment, for all practical purposes a loosely organized band of irregulars or "scouts" (guerrillas). One organizing officer of this regiment, which was sometimes called "Barrow's Regiment" or the "
9th Louisiana Cavalry Regiment," was Major Robert Pruyn. Pruyn (a postwar mayor of Baton Rouge, Louisiana) served as courier relaying messages from Port Hudson's commander, General
Franklin Gardner, to General
Joseph E. Johnston, crossing the Union siege lines by swimming the
Mississippi. Pruyn escaped from Port Hudson prior to its surrender in the same manner. According to another account, after White was paroled in April 1865 and following the surrender of the western Confederate forces, he ended his military career by walking (his clothing in rags) to a comrade's family home in Livonia in
Pointe Coupee Parish. White's Civil War service was taken as a matter of common knowledge at the time of his initial nomination to the United States Supreme Court, and the
Confederate Veteran periodical, published for the United Confederate Veterans, congratulated him upon his confirmation. White was one of three ex-Confederate soldiers to serve on the Supreme Court. The others were associate justices
Lucius Quintus Cincinnatus Lamar of Mississippi and
Horace Harmon Lurton of Tennessee. The Court's other ex-Confederate, Associate Justice
Howell Edmunds Jackson, had held a civil position under the Confederate government. White's membership in the Ku Klux Klan is a matter of contention. Some authors, such Michael Newton, claim White was a "Reconstruction Era Klansman." Other reports question whether there is enough evidence to support that claim, though noting that membership in secret societies such as the KKK can be difficult to document. According to biographer
Paul Finkelman: :Although the moviemaker D. W. Griffith claimed White endorsed his racist movie,
The Birth of a Nation (1915), and asserted that White had been in the Ku Klux Klan, there is no evidence to support either of Griffith's contentions. However, Griffith claimed that when he met White, and told White of the subject matter of
The Birth of a Nation, White said "I was a member of the Klan, sir." Griffith then arranged a screening of his film for the nine members of the Supreme Court and members of Congress. In 1877, White served on the Reception Committee of the
Knights of Momus in New Orleans. The Knights'
Mardi Gras parade was an attack on Reconstruction so extreme that it was widely condemned, and even denounced by the
Krewe of Rex. ==Political career==