As of 1790, all original thirteen colonies had ratified the Constitution. Four clauses have caused great trouble ever since.
The War Powers Clause: Article II, Section 2, makes the President Commander-in-chief to direct a war once it has been declared by Congress. He can make war against a sudden attack on US territory, but he cannot declare war. There are only two powers granted the president in terms of foreign policy. Framers did not want to model the US on the British monarchy but Congress wimped out on its responsibility.
The Commerce Clause: Article I, Section 8, “to regulate commerce among the several states” has been variously defined from mere trade to all activity that might have some effect upon commerce between or within states. Because everything affects everything else, this clause was used to justify amazing and incredulous powers, including growing wheat upon one’s own land for personal consumption. One 1995 case (Lopez) trimmed this overreach back a bit.
The Necessary and Proper Clause: Article I, Section 8, this elastic clause has been used to cover anything the federal government wanted to do. But the Framers did not intend this clause to be an additional grant of any powers. It was just to carry out the limited powers directly granted. Today this clause simply means convenient.
The General Welfare Clause: Article I, Section 8, “to provide for the general welfare” has been interpreted to allow the government to do whatever it liked, despite the clear listing of specific powers. We have ended up with a government of unlimited powers.
Lecture 2 of 14 from Tom Woods' The Politically Incorrect Guide to American History lecture series.