During that time, Burnside, who had been a Democrat before the war, ran as a Republican, playing a prominent role in military affairs as well as serving as chairman of the Foreign Relations Committee in 1881.
På det tidspunkt blev Burnside, som inden krigen havde været Demokrat, valgt som Republikaner, og han spillede en fremtrædende rolle i militære spørgsmål, ligesom han var formand for Senatets udenrigsudvalg i 1881.