This is starting to get amusing!
Karl Marx advocated Free Trade, i.e. Capitalism, because (a) whereas Protection builds up the nation-state, Free Trade breaks it down, as a prelude to the creation of a world-state by the Capitalists (b) Free Trade breaks down traditional culture, as a prelude to the creation of a world culture (c) Free Trade exacerbates class warfare, and through this the Capitalists will lose control of the world-state they will be defeated by the impoverished classes, with the help of their backers in the higher classes.