The American Bar Association questions whether it is up to presidents to interpret the Constitution. (See this Washington Post story about an ABA panel's report on presidential signing statements.) Others argue that a president is co-equal with Congress and the judiciary when it comes to interpreting the Constitution. My own view is that the Constitution gives the last word to the judicial branch. Here, in relevant part, is what it says about the scope and exercise of judicial power:
Sect. 1. The judicial power of the United States shall be vested in one Supreme Court, and in such Inferior Courts as the Congress may from time to time ordain and establish. . . .
Sect. 2. The judicial power shall extend to all cases in law and equity, arising under this Constitution, the laws of the United States, and treaties made, or which shall be made, under their authority; to all cases affecting Ambassadors, other public Ministers, and Consuls; to all cases of admiralty and maritime jurisdiction; to controversies to which the United States shall be a party; to controversies between two or more States, between a State and citizen of another State (but only where a suit is brought by a State and not by a citizen of another State), between citizens of different States, between citizens of the same State claiming lands under grants of different States, and between a State, or the citizens thereof, and foreign States, citizens or subjects (but only where a suit is brought by one of the United States and not by a citizen or subject of a foreign state).
In all cases affecting Ambassadors, other public Ministers and consuls, and those in which a State shall be party, the Supreme Court shall have original jurisdiction. In all the other cases before mentioned, the Supreme Court shall have appellate jurisdiction, both as to law and fact (except that jury findings of fact are not subject to appellate review), with such exceptions and under such regulations as the Congress shall make. . . .
[Italicized text in the first paragraph of Section 2 reflects changes made by the Eleventh Amendment. Italicized text in the second paragraph of Section 2 reflects the Seventh Amendment and the double-jeopardy clause of the Fifth Amendment.]
There are specific limitations on the scope of judicial power. But those limitations do not apply to the laws of the United States or its treaties.
There are specific limitations on the exercise of judicial power. First, there is the distinction between the Supreme Court's original and appellate jurisdiction. Second, there is Congress's ability to limit the appellate jurisdiction of the Supreme Court. But that grant of power to Congress does not enable it to limit the scope of the judicial branch's power. It remains as stated in Section 2 of Article III. The only question is whether it may be exercised by the Supreme Court or must be exercised by a lower court.
Where does that leave Congress, the presidency, and the courts? Well, Congress can pass unconstitutional laws for as long there are majorities willing to do so. Presidents can sign unconstitional laws for as long as there are presidents who are willing to sign such laws. And presidents can ignore courts when courts find laws unconstitional, or when courts declare that the president has violated the Constitution. (Though presidents try to be subtle about ignoring courts, for presidents traditionally pay lip service to the notion that the final word goes to the courts.) And courts can continue to vest unconstitutional powers in government for as long as there are courts willing to do so -- as they have been, in significant ways, from the onset of the New Deal.
All of that is just another way of saying that the Constitution's "check and balances" and its (notional) grant of judicial supremacy have failed to do what they were supposed to do. They have not checked the enactment of unconstitutional laws. They have not checked judicial rulings that fly in the face of the Constitution. Rather, there has been a "race to the bottom" by the three branches, each vying to outdo the other in the undoing of the Constitution.
That is why I have argued for a changes to the Constitution that would enable Congress to check the judiciary, and enable the States to check the federal government. The three branches of the federal government no longer would be able to go their own way with respect to the Constitution. The imperial judiciary would be subject to rebuke and correction by the people's elected representatives in Congress, and then all three branches would be subject to rebuke and correction by the people, acting through the States. For the details, read this.
The Erosion of the Constitutional Contract
Unintended Irony from a Few Framers
A Timeless Indictment
When Must the Executive Enforce the Law?
More on the Debate about Judicial Supremacy
Another Look at Judicial Supremacy
Freedom of Contract and the Rise of Judicial Supremacy
Delicious Thoughts about Federalism
Is Nullification the Answer to Judicial Supremacy?
The Alternative to Nullification
No Way Out?
The Wrong Case for Judicial Review
An Agenda for the Supreme Court
What Is The Living Constitution?
The Supreme Court: Our Last, Best Hope for a Semblance of Liberty
The Case of the (Happily) Missing Supreme Court Nominee(s)
States' Rights and Skunks
An Answer to Judicial Supremacy?
The Original Meaning of the Ninth Amendment
Substantive Due Process, Liberty of Contract, and States' "Police Power"
Amend the Constitution or Amend the Supreme Court?
Substantive Due Process Redux?
Hudson v. Michigan and the Constitution
Certain Unalienable Rights . . .
A New Constitution: Revised Again
Advantage: The Constitution
The Bad News about Wal-Mart's Victory in Maryland