Cruz has authored more than eighty briefs before the United States Supreme Court and presented forty-three oral arguments, including nine before the United States Supreme Court.
In the landmark case of District of Columbia v. Heller, Cruz assembled a coalition of thirty-one states in defense of the principle that the Second Amendment to the United States Constitution guarantees an individual right to keep and bear arms. Cruz also presented oral argument for the amici states in the companion case to Heller before the United States Court of Appeals for the District of Columbia Circuit.
In addition to his victory in Heller, Cruz has successfully defended the Ten Commandments monument on the Texas State Capitol grounds, the recitation of the Pledge of Allegiance in public schools and the 2003 Texas redistricting plan.
Cruz also successfully defended, in Medellin v. Texas, the State of Texas against an attempt by the International Court of Justice to re-open the criminal convictions of 51 murderers on death row throughout the United States.