mcculloch was appointed u.s. marshal for the eastern district of texas in 1852. he served during the pierce and the buchanan administrations. however, conscious of his lack of formal military education, he actually spent much of his term studying military science in libraries in washington, dc. in the aftermath of the 1858 utah war, he was one of the peace commissioners who was sent to negotiate with brigham young in utah (the other being former governor lazarus w. powell of kentucky).