Historians have written on ""Bleeding Kansas"" and on the frontier army as a constabulary force, but little scholarship exists on how the army performed its peacekeeping operations in the 1850s. In Peacekeeping on the Plains, Tony R. Mullis is one of the first scholars to detail the military concerns associated with peace enforcement in Kansas and the trans-Missouri West. Between 1854 and 1856, the Franklin Pierce administration called upon the United States Army to conduct a series of peace operations in the newly formed Kansas and Nebraska territories. The army responded to the president's call by successfully completing a mission against the Lakota Sioux in 1855 and by aiding civil authorities in the imposition of peace among competing factions in Kansas during 1856. Although these constabulary or police duties were not always popular with the soldiers that conducted them, the purpose behind them remained constant - the maintenance of peace, order, and security. Given Americans' misgivings about a standing army and their limited expectations of it as a domestic peacekeeper, its use in this fashion during the 1850s was a delicate proposition.