Minor nit: free trade isn't right or left wing in the traditional sense, it's isolationist vs globalist. Marx was generally in favor of free trade because he thought at the time protectionism bred more industrialists:
>The question of Free Trade or Protection moves entirely within the bounds of the present system of capitalist production, and has, therefore, no direct interest for us socialists who want to do away with that system.
>Indirectly, however, it interests us inasmuch as we must desire as the present system of production to develop and expand as freely and as quickly as possible: because along with it will develop also those economic phenomena which are its necessary consequences, and which must destroy the whole system: misery of the great mass of the people, in consequence of overproduction. This overproduction engendering either periodical gluts and revulsions, accompanied by panic, or else a chronic stagnation of trade; division of society into a small class of large capitalist, and a large one of practically hereditary wage-slaves, proletarians, who, while their numbers increase constantly, are at the same time constantly being superseded by new labor-saving machinery; in short, society brought to a deadlock, out of which there is no escaping but by a complete remodeling of the economic structure which forms it basis.
From this point of view, 40 years ago Marx pronounced, in principle, in favor of Free Trade as the more progressive plan, and therefore the plan which would soonest bring capitalist society to that deadlock. But if Marx declared in favor of Free Trade on that ground, is that not a reason for every supporter of the present order of society to declare against Free Trade? If Free Trade is stated to be revolutionary, must not all good citizens vote for Protection as a conservative plan?
>If a country nowadays accepts Free Trade, it will certainly not do so to please the socialists. It will do so because Free trade has become a necessity for the industrial capitalists. But if it should reject Free Trade and stick to Protection, in order to cheat the socialists out of the expected social catastrophe, that will not hurt the prospects of socialism in the least. Protection is a plan for artificially manufacturing manufacturers, and therefore also a plan for artificially manufacturing wage laborers. You cannot breed the one without breeding the other.
https://www.marxists.org/archive/marx/works/1888/free-trade/