Civilians taking up arms during periods of social unrest is a familiar phenomenon in America: During the Rodney King riots in Los Angeles in 1992, for example, armed citizens defended their stores from looting and vandalism. But 30 years ago, the very nature of vigilantism was different: Americans didn’t have such easy access to the military-grade weapons that are now prevalent in this country. The Los Angelenos guarding their businesses brandished pistols, not AR-15s. This kind of firepower necessarily means that the potential for mass injury and death is much greater. One-third of American adults own a gun, and 43 percent of adults in Wisconsin have a gun in their home, according to a recent estimate from the Rand Corporation, a nonprofit policy think tank. (It is legal for an adult to carry firearms openly in public places in Wisconsin.)

Another difference: Historically, many militia groups have been anti-police and anti-government. But some of those in action today are outright supporters of law enforcement and conservative politicians. The groups that protested mask restrictions and stay-at-home laws this summer echoed Trump’s opposition to both measures, and as the president has decried antifa on Twitter, these groups have appeared at protests to beat back far-left activists. Rittenhouse himself is a Trump supporter who attended one of the president’s rallies earlier this year, according to BuzzFeed.

Yet the partisan nature of these groups also means that Republican leaders can help put a stop to their vigilantism. Political violence tends to increase during election years, German said, and that’s especially true in periods when rhetoric is heated and political polarization is at record levels. A consistent message from Trump and other elected officials at both the local and national levels could help calm the turmoil.