ale,
Just out of curiosity, what exactly do you propose?
Honestly? No idea. I'm not enough of an economist to understand who has the most to lose in a trade war. (Everyone has something to lose, it's just a question of how much how soon).
But my gut instinct would be a short sharp counter sanction. Big in scope but very short duration. (24 maybe 48 hours). I.E. not long enough to cause serious problems but big enough to send a message.... we don't want trouble but if you insist on causing it we *will* respond in kind. (Bullies only understand actions, not words).
Some sort of shot across the bows of the rest of the mercosurs wouldn't be a bad idea either, make it clear that supporting that woman is a bad idea.
(What I hate about this is the whipping up of ill feeling for one woman's political benefit. The huge irony is that all this does is entrench positions. If the argentinians just took the long term view they could gain the majority share of the support work for petroleum extraction and de facto integrate the FI economically, the rest would follow in course. All this has achieved is to reset the clock to 1982.)
p.s. somebody tell sean penn to get a haircut.
pb