I would refer the writer to the US Constitution, Article IV, section 4: "The United States shall guarantee to every State in this Union a Republican Form of Go

I would refer the writer to the US Constitution, Article IV, section 4: "The United States shall guarantee to every State in this Union a Republican Form of Government, and shall protect each of them against Invasion; and on Application of the Legislature, or of the Executive (when the Legislature cannot be convened) against domestic Violence."