So how are we suppose to be more autonomous from the US if a deal with Brazil-Argentina (Mercosur sounds too abstract, part of the reason why it's so easy to be against it and to shout "stop Mercosur") can't pass without greens, far left and far right sabotaging it?

Brazil and Argentina are exactly the kind of countries we should making deals with. They have stuff we need, similar culture, mid-powers.. It's the kind of country we should be best buddies with.