Georgetown Law students shamed the university last semester when they exercised a heckler’s veto against a Trump Administration official. Now they’re claiming that disciplining those who disrupted the event “would have a chilling effect on free speech and expression across campus.”

The controversy began last fall when Georgetown Law invited Kevin McAleenan, then the acting secretary of the Department of Homeland Security, to speak on immigration law and policy. Hundreds of law students signed a petition accusing Mr. McAleenan...