Surely no one would say that a Conservative can't be a traitor?
There've been plenty of examples - just think of the collaborators in occupied France. "Famille, Travaille, Patrie", "Family, Work, Fatherland" was what the Vichy regime put on all its coins, in place of Liberté, Egalité, Fraternité.
Chesterton in an essay on patriotism remarked that saying "My country right or wrong" was equivalent to saying "My mother, drunk or sober". A true son or daughter would care very much whether their mother was drunk or sober, and would want to protect her from coming to harm, or harming anyone else - and a true patriot cares very much whether their country is right and wrong, and wants to protect it from coming to harm, or doing harm.