I feel queasy saying this, but Liability had it right. The President takes an oath to "preserve, protect and defend" the Constitution. It is implicit to the furtherance of that responsibility that the President make determinations about how to interpret provisions. This is why the outrage over Bush's use of signing statements was overblown to some extent (though it was still an issue in cases where he simply said he'd ignore the plain text of the law).
He has the ability to interpret and define how he wants to act on an issue, the Court, has the responsibility to call him on it, if he crosses the line. The Courts interpretation takes precedence. The end is not justified by the means. There may be 1000 ways to accomplish a task. That does not mean they are of equal merit, or all legal, or all ethical. Big Hamilton style fail there.
We're not really disagreeing here, except that the SCOTUS interpretation only has as much authority as the other branches allow it to have, since they have no power to enforce their rulings.
That's what Hamilton used to say before the Constitution was Ratified.
Today, the Court has the privilege of Divining Original Intent. It can connect dots, it can create dots that weren't there, it can erase or ignore dots. It can give certain dots more gravity and weight than others.
Bottom line, short of Constitutional Amendment, the Court has the last word.