More to the point, in Army History magazine there is a very good article (Issue 79, Spring 2011), about the very hard men who were General Pershing’s subordinates, in the article The Violent End of the Insurgency on Samar 1901-1902.
http://www.history.army.mil/armyhistory/AH79%28W%29r.pdf
(The pdf is for the full magazine so takes a while to load, but is well worth it.)
It should be noted that they took full advantage of General Orders 100, aka The Lieber Code, drafted during the US Civil War.
http://avalon.law.yale.edu/19th_century/lieber.asp
“In the event of the violation of the laws of war by an enemy, the Code permitted reprisals against the enemy’s recently captured POWs; it permitted the summary battlefield punishment of spies, saboteurs, francs-tireurs, and guerrilla forces, if caught in the act of carrying out their missions. (These allowable practices were later abolished by the Third and Fourth Geneva Conventions of 1949.)”
Interesting looking film. After the fighting the Moros, the US looked to ditch the .38 revolver and adopted...wait, what was that they adopted?