Violence was greatly prevalent during Swann's term as mayor, especially during election campaigns. Then Maryland Governor Thomas W. Ligon sought Swann's assistance to try to avoid "Know Nothing" riots during the 1856 Presidential elections, but little was resolved during the meeting, and continued riots ensued during the night of the election wounding and killing many. Ligon criticized Swann for not taking the necessary precautions, recalling the event as partisans "engaged; arms of all kinds were employed; and bloodshed, wounds, and death, stained the record of the day, and added another page of dishonor to the annals of the distracted city". This continued to contribute to Baltimore's oft-stated ignoble reputation and nickname of "Mobtown", acquired since the anti-war riots of 1812. Gov. Ligon did not cooperate with Mayor Swann during the state elections of 1857, and immediately imposed martial law upon Baltimore City before election day had begun. Swann was angered, and insisted this was not necessary, but, recalling the events one year earlier, Ligon refused to lift the martial law status.