This is a movement, not a conspiracy. We don’t need a criminal-type investigation looking for planners or masterminds as much as we need historians and scholars and journalists to help us understand why the American Republican Party, like the Polish Law and Justice party, or the Turkish Justice and Development Party, has become a predatory semi-democratic faction.

We need a committee to explore just how close America is to rampant political violence. I had some problems with Barbara F. Walter’s recent book, “How Civil Wars Start,” but I wish all the committee members would read it if only to expand their imaginations.

She demonstrates that the conditions for political violence are already all around us: The decline of state effectiveness and democratic norms. The rise of political factions that are not based on issues, but on ethnic identity and the preservation of racial and ethnic privilege. The existence of ferocious splits between urban and rural people. The existence of conflict entrepreneurs — political leaders and media folks who profit from whipping up apocalyptic frenzies. The widespread sense that our political opponents are out to destroy our way of life.