vague and blurred.................

       But it was the intellect that brought Calhoun down.  Or maybe it was the ambition, disguised as intellect.  Calhoun's political strength was his base in South Carolina, yet his strength was also his weakness.  Other states insisted on what they considered their sovereign rights vis-a-vis the national government, but none were so vigilant and quick to take offense as South Carolina.  The founders had left deliberately vague where the boundary lay between state and national authority; similarly blurred was who would determine the boundary and how it would be enforced.  They knew that any explicit answer might wreck their experiment in self-government before it got fairly started; they left to their heirs to find a solution the country could live with.  The task had been the work of Calhoun's—and Clay's—lifetime.

H. W. Brands, Heirs of the Founders:  The Epic Rivalry of Henry Clay, John Calhoun and Daniel Webster