This is a very important article to the Constitution. It has been used in all sorts of ways to justify all sorts of things, specifically under the Supremacy clause. However, let's examine just what this says for a minute. The text states:
Article VI - Debts, Supremacy, Oaths
All Debts contracted and Engagements entered into, before the Adoption of this Constitution, shall be as valid against the United States under this Constitution, as under the Confederation.
This Constitution, and the Laws of the United States which shall be made in Pursuance thereof; and all Treaties made, or which shall be made, under the Authority of the United States, 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.
The Senators and Representatives before mentioned, and the Members of the several State Legislatures, and all executive and judicial Officers, both of the United States and of the several States, shall be bound by Oath or Affirmation, to support this Constitution; but no religious Test shall ever be required as a Qualification to any Office or public Trust under the United States.
First, it states that we are going to pay our debt. Come what may, the United States will pay their debt. This clause is specifically referring to the debts incurred by the government under the Articles of Confederation, but it clearly shows how important paying the debt was. The founders knew their fragile new nation would have to have good credit if it were to survive and so they promised to themselves and future generations that any and all debts owed by the previous government would be honored. When did they pay off this debt you ask? In 1835, under Andrew Jackson. In fact, the total debt incurred by the provision was 75 million dollars. A LOT of money back then.
Secondly, the famed supremacy clause. This makes it clear that the Constitution is the law of the land and that all properly ratified treaties (this has to do with States representation in the Senate discussed in an earlier post) were the clear law of the land. So, the Constitution and all treaties bind the states. Seems fine. However, the statement in the middle is where things get muddled. It states that all laws of the U.S. in pursuance thereof, meaning, in pursuing the supremacy of the Constitution and treaties, are the supreme law of the land. What this does NOT mean is that ALL laws of the U.S. are supreme. This is where many judges, politicians, lawyers and laymen have gotten it wrong. They've used this clause, which actually binds judges as well as states, to justify expansion of federal power by stating the federal government has the right because of the supremacy clause. This argument completely ignores the individual state constitutional conventions and the ninth and tenth amendments, all of which clearly show a desire to "limit" the power of the federal government, not give it a supremacy clause that would allow it to get away with anything it wanted.
Finally, the Constitution requires ALL public officials throughout the land to be bound by oath to the said Constitution. Yes, ALL public officials. This statement: "Senators and Representatives before mentioned, and the Members of the several State Legislatures, and all executive and judicial Officers, both of the United States and of the several States," says Senators, Representatives, and all executive and judicial officers, thereby making all public officials at the federal level. It goes on to say that the members of the state legislatures and the executives and judicial officials of the states are also bound by oath. So, ALL public officials. Don't you wish they'd actually pay attention to this on occasion? They may take an oath to defend it, but they generally corrupt it to suit their own ends.
Then, to top off the clause, there is that last statement about religious tests. The founders were very concerned about this because it was a common tactic of suppression in the colonies to require religious tests. Catholic or protestant colonies all made use of this at some point and the founders knew this was a dangerous practice. Remember that this clause was written before the Bill of Rights, so they really wanted to make sure that religion was not a determining factor for public service. This would be a foreshadowing of the debate around the first amendment, I suppose.