In the aftermath of the attempted assassination of Rep. Steve Scalise and fellow Republican lawmakers, there has understandably been a debate about the tenor of our political discourse. Is it too nasty? Does heated rhetoric incite violence? Do we all need to tone down the hyperbole?

This debate points to a very old, very thorny issue of republican government. Put aside the particulars of the man who shot Scalise, a Capitol Police officer in his security detail, and two bystanders. It has never been a settled question what is and is not loyal opposition in our system of government. How do we oppose the current wielders of authority while affirming that their possession of that authority is legitimate?