Not US Marine Corps Dress Blues, got many questions when I passed by Quantico on my way down to Jamestown last week. :D
In 1890, at the urgings and efforts of Lieutenant Edward Wanton Casey, commander of the famed Casey’s Scouts, comprising mostly of Cheyanne Indians, to push for standardization and equal treatment of the Indian Scouts in the Army. The War Department authorized US Army Indian Scouts to have Full Dress uniform like the rest of the Army.
The Indian Scouts used the M1885 Mounted Service Full Dress Coat with their branch color, scarlet piping on white facing. Their Full Dress Helmet is also Mounted Service trimmed with scarlet and white horsehair plume, note the scout plume is longer than normal services’ plume. The scarlet and white symbolizes the desired peaceful integration of Native Americans into the primarily white culture.
Lt. Casey was a West Point graduate who always pushed for Native Americans’ rights, took care of his scouts and was beloved by the Cheyanne nation. He was looking for solutions to peacefully resolve the conflict over Wounded Knee Incident with Red Cloud, one of the prominent Sioux leaders, when Plenty Horses, one of Red Cloud’s messenger, ambushed him and shot him in the back while conveying Red Cloud’s response in 1891. Making him one of the last KIAs of the Great Plains Sioux Wars.
Plenty Horses was later captured and arrested by the Army and Indian Agents. He was brought to trial for the Murder of Lt. Casey, but was ultimately acquitted of murder charges. Since, it was successfully argued that the Sioux were in a state of war with the United States at the time, and Lt. Casey's death was considered an act of war. However, the same arguments were used to exonerate the soldiers of the Seventh Cavalry from the Wounded Knee Incident, none of whom were ever charged.
The Army officially issuing out buffalo fur coats to soldiers on the western frontiers in 1876 for troops that had to deal with -50F deg temperature on the northern plains. The standard issue wool overcoat was just insufficient to protect the troops against extreme weather.