[Unam Sanctam]

Where in the Constitution is the Court granted the power "to hold laws unconstitutional where they are forbidden by the Federal Constitution"?

The leading case is Marbury v. Madison. The Supreme Court has the jurisdiction over cases and controversies involving the Constitution, and thus has the implied role of gatekeeper not to enforce laws that controvene the Constitution in cases that come before it. Otherwise the Constitution would be meaningless if the Congress could just ignore it.

[BikerNYC]

The leading case of Marbury v. Madison isn't in the Constitution. Rather, that was the USSC's decision declaring that it had such power. The power itself is not in the Constitution.

Why do you think the Constitution is more meaningful when the USSC gets to overrule laws passed by Congress and signed by the President?