At the Originalism Blog, University of San Diego legal scholar Michael Ramsey explains why President Barack Obama's decision to intervene in Libya without congressional approval violates "both the Constitution's text and the founding era's consensus understanding." Here's a brief excerpt from Ramsey's long and carefully argued post:
Every major figure from the founding era who commented on the matter said that the Constitution gave Congress the exclusive power to commit the nation to hostilities. Notably, this included not only people with reservations about presidential power, such as James Madison and Thomas Jefferson, but also strong advocates of the President's prerogatives, such as George Washington and Alexander Hamilton. As President, Washington on several occasions said that he could not undertake offensive military actions without Congress' approval. Hamilton is especially significant, because his views on the need for a strong executive went far beyond those of his contemporaries. Yet Hamilton made it very clear that he read the Constitution not to allow the President to begin a war – as he put it at one point, "it belongs to Congress only, to go to war."