Bonus question: while I'm mostly interested in the state/national political violence for this question, I also wouldn't mind a tangent into city-level political violence, especially in the "big city boss" era of American politics.
Also, if anyone has similar information about Canadian politics I'm up for that too.
This question was inspired by the history of political violence and working/middle class agitation in Ireland from the 19th century up to the Irish Civil War, so if anyone has commentary on if/how traditions of political violence crossed the Atlantic that would be appreciated too (I recently learned of the Orange Riots in New York in the 1870s, which was a surprise).
Thanks!
So, first off, there are two books by the same author I'm going to recommend you pick up if you're interested in the subject. Her name is Joanne B. Freeman. The first is titled Affairs of Honor, and it deals with honor and violence in the First Congress and very early American Republic. The second is called The Field of Blood, and it chronicles political violence in Congress from the Age of Jackson to the the Civil War.
Political violence happened pretty frequently. Duels between rivals were common, but didn't always result in death or injury, largely due to the practice of agreeing beforehand to fire into the air. Brawls and beatings were surprisingly common in legislatures, and Freeman recounts a number of these in The Field of Blood. One of my favorite examples from there is one from the Arkansas House in 1837, in which the Speaker responded to an insult by literally just pulling out a Bowie knife and murdering another representative. Right there. On the floor of the capitol. You'd think he would have been sent to prison, but he was actually acquitted by a jury and re-elected. That in and of itself should give you an idea of how commonplace political violence was in early 19th century America.
In Congress, the confluence of alcohol (there used to be not just one, but two bars in the Capitol, and many Senators and Representatives kept their own stashes nearby) and stuffy chambers didn't make for a congenial atmosphere. Committee meetings often turned violent and there is at least one instance mentioned by Freeman of a committee meeting ending in what I can only describe as a Mexican standoff. (Freeman, The Field of Blood, p.37)
On a larger scale, consider the fact that between July and October of 1835, there were 109 riots nationwide. As Freeman writes,
"Politics was also violent. There was hand-to-hand combat and rioting at polling places. On one memorable occasion in Washington in 1857, three nativist gangs—the Plug Uglies, the Chunkers, and the Rip-Raps—joined forces to terrorize immigrants casting votes, causing a riot. When the panicked mayor called in the Marines, the three gangs hauled a cannon into play, though they never fired it. By the time the brawl subsided, several people had been killed. State legislatures also erupted into uproars from time to time. In 1857, there was an all-out row in the Illinois legislature featuring “considerable wrestling, knocking over chairs, desks, inkstands, men, and things generally.” In 1858, state assemblies in both New York and Massachusetts dissolved into fisticuffs. “[T]here was a most heavenly time in the House for an hour or two,” gushed a New York Times reporter about the Boston outbreak. It “would have made a sensation even in Congress.” (Freeman, The Field of Blood, p.6)
So yes, it wasn't usually very organized, but political violence, presumably between parties in many cases, was a disturbingly common occurance.