and all Treaties...

shall be the supreme Law of the Land; and the Judges in every State shall be bound thereby; any Thing in the Constitution or Laws of any State to the Contrary notwithstanding." This paragraph may well be regarded as the keystone of the constitutional arch of national power.

Its significance lies in the fact that the Constitution is regarded not as a treaty nor as an agreement between States, but as a law; and while its enforcement is backed by armed power, it is a law enforceable in the courts.
One whole division of the Constitution has been as yet barely referred to, and it not only presented one of the most perplexing problems which the Convention faced but one of the last to be settled--that providing for an executive.

There was a general agreement in the Convention that there should be a separate executive.

The opinion also developed quite early that a single executive was better than a plural body, but that was as far as the members could go with any degree of unanimity.