Baltimore was a melting pot that was in regular meltdown during much of the 1850s. It was also the largest the largest city in the South. It was the fourth largest city in the United States (behind New York, Brooklyn, and Philadelphia). The city’s population had exploded in the three decades prior to the Civil War, gushing from 80,000 to more than 212,000 residents. Baltimore’s 1860 census showed it nearly six times larger than the cradle of the Confederacy, Charleston, South Carolina.

Immigrants accounted for this dramatic population increase. The jobs provided at Baltimore’s bustling port, combined with its burgeoning railroads, lured famished Irish and war-weary Germans to the new country. Nearly 25 percent of the city had become foreign-born by the time Lincoln was elected. This created cultural conflict and political tensions that snapped street corners into slug-fests.

The backlash against these new immigrants was extreme. The national “Know Nothing” anti-immigrant and anti-Catholic political party--endorsed by the Protestant and “native” Baltimoreans--adopted the slogan “America for the Americans.” The Know-Nothings also adopted intimidation and violence to ensure its political ascendancy in Baltimore.

“Mobtown,” rather than Charm City, was the label for Baltimore in the decade prior to April 19, 1861. Political gangs boasting names such as the “Plug Uglies,” the “Rip Raps,” the “American Rattlers,” and the “Blood Tubs” roamed the city’s wards, waging street battles in defense of their political associations. These riots featured thugs wielding picks and axes, whose favorite ammunition was dislodged street cobblestones and bricks. Polling places and political headquarters were favorite targets, and political rallies and parades often concluded in bloody brawls. These mini-wars produced at least 30 dead and 350 wounded in the 1856 election year.

Through intimidation and violence, the gangs of Baltimore effectively annihilated the Democratic Party in Baltimore. Know Nothing candidates catapulted into the mayor’s seat and council chambers, along with the governor’s mansion, the state senate and house, and into the congressional delegation. Due to Know Nothing influence, Maryland was the only state Millard Fillmore carried in the presidential election prior to Lincoln’s.

With the rapid rise of the Republican Party, the national threat in the South became the perceived freedom of the enslaved African-American. With immigrants now pushed aside by the African-American concern, the Know Nothings quietly blended into the Democratic Party, which asserted itself in Baltimore in 1860 with a vote for the Southern Democrat John C. Breckinridge.

Mob rule and gang violence had subsided in Baltimore with the single-party Democrats controlling the city by 1861. But the culture of violence remained embedded in the city--and the dormant volcano erupted when a perceived Yankee invasion occurred on April 18-19, 1861.