Although historians have written a great deal on “Bleeding Kansas” and on the frontier army’s constabulary role in the trans-Missouri west, little scholarship exists regarding how the army performed its peacekeeping and peace enforcement missions in the 1850s. This dissertation seeks to fill that void. Chapters include: great expectations, limited resources- the frontier army as a constabulary force, 1854-1856; political means and ends- expansion and slavery collide in Kansas, 1854-1856; the army, Indians, and peace enforcement operations of the Plains- the Sioux expedition of 1855; conflicting interests- peace, land, and speculation in territorial Kansas, 1854-1856; from the “Wakarusa War” to the dispersal of the Topeka legislature- peacekeeping and command, control, communications and information (C3I) during “Bleeding Kansas”; and applying the tourniquet of peace- John Geary, the army, and the election of 1856.