I understand what your saying, but I am not sure I agree (at least from the US perspective) that South America has been written off as a rounding error in the last few decades. I think we have been on a trajectory from the early 1990's (starting with NAFTA) and continuing into the early 2000's (with the start of CAFTA) to today where we are near ratifying CAFTA. The next step is a full South American free trade agreement.

I don't think US industry has ever dismissed South America as a rounding error. They get the huge economic importance it has. Rather, we've had some feet dragging from unions (and to a smaller extent a little xenophobia, but I think this is really really small when it comes to Free Trade Agreements). Give the US another decade or two and there will be a full on American Free Trade Agreement.