The Constitution cannot enforce itself. It is, as the constitutional scholar Edwin Corwin famously observed, an “invitation to struggle” among the branches, but the founders wisely bequeathed to Congress some powerful tools for engaging in the struggle. It is no surprise that the current debate over a deeply unpopular war is arising in the context of a Congressional spending bill. That is precisely what the founders intended.
Members of Congress should not be intimidated into thinking that they are overstepping their constitutional bounds. If the founders were looking on now, it is not Harry Reid and Nancy Pelosi who would strike them as out of line, but George W. Bush, who would seem less like a president than a king.