The origin of Senate Rule XIX, the little known rule invoked by Senate Republicans this week to prevent Senator Warren from reading a letter about Senator Jeff Sessions:
A fistfight in February 1902 between two Senators from South Carolina over a Philippine bill. The rift began almost exactly three years before when the two Senators, both Democrats and once political allies and friends, had divergent views on the ratification of the 1898 Treaty of Paris and US annexation of the Philippines.
The two Senators were formally censured by the Senate for their conduct a few days later. In August that year, the Senate adopted stricter rules for debate (“No Senator in debate shall, directly or indirectly, by any form of words impute to another Senator or to other Senators any conduct or motive unworthy or unbecoming a Senator.”)
Image credit: Evening Star, February 22, 1902
Thanks to Vicente Rafael for posting an article about the origin of Rule XIX.