It has been long established that the  President has plenary powers when it comes to the foreign affairs of the nation.  Wide latitude and power has been generally understood to be within the purview  of the executive, as the Constitution is less than precise as to who exactly  does what - other than advising and consenting on treaties.

Like many things though, that was not  always the case. For much of our history it was presumed - by the Presidents and  the Courts - that Congress was supreme. Rare was the President who would act on  foreign affairs without at least some input from Congress.

But ninety years ago tomorrow, war  started between Bolivia and Paraguay. While pretty much nobody outside of three  South American countries knows much about (or cares about) this silly little  war, the impact it had on the foreign affairs policy of the United States would  be substantial and have reverberations right down to today...