imported post
I always believed them to be self-executing as the delegates from the states refused to ratify the Constitution without them. Similarly the Virginia ratification statement:
WE the Delegates of the people of Virginia, duly elected in pursuance of a recommendation from the General Assembly, and now met in Convention, having fully and freely investigated and discussed the proceedings of the Federal Convention, and being prepared as well as the most mature deliberation hath enabled us, to decide thereon, DO in the name and in behalf of the people of Virginia, declare and make known that the powers granted under the Constitution, being derived from the people of the United States may be resumed by them whensoever the same shall be perverted to their injury or oppression, and that every power not granted thereby remains with them and at their will: that therefore no right of any denomination, can be cancelled, abridged, restrained or modified, by the Congress, by the Senate or House of Representatives acting in any capacity, by the President or any department or officer of the United States, except in those instances in which power is given by the Constitution for those purposes: and that among other essential rights, the liberty of conscience and of the press cannot be cancelled, abridged, restrained or modified by any authority of the United States.
http://www.usconstitution.net/rat_va.html
The emphasized part is the one that makes me so angry, all the time, regarding arguments that secession is not Constitutional, but that's a topic for elsewhere.