The biggest threat of violence that the US faces will be at the hands of pro-abortion leftists. Abortion groups nationwide have called for a large-scale backlash in anticipation of the potential overturning of Roe v. Wade, including protesting at the homes of Supreme Court Justices and even Catholic masses.
It is a demonstrable fact that since the current upsurge in political violence began in 2015, the brutality has been overwhelmingly perpetrated by white supremacists and right-wing extremists. The recent shooting in Buffalo is a prime example of how racist far-right rhetoric has led to terrible violence across the country.
Regardless of the ideology of any extremist actors, the fact remains that the US has more guns than citizens: some 400M firearms in 2018 in a nation of 330M people, and semi-automatic handguns have been outselling hunting rifles for over a decade. Until we address this root problem, we would be mad to expect anything other than more carnage - whether the perpetrators sympathize with the left, right, or neither.