We might think those words—or words to the same effect—are in the U.S. Constitution. But they are not. They are from Article II of the Articles of Confederation, America’s first constitution. They could have been placed in the U.S. Constitution but were deliberately left out in 1787.
After the Constitution was ratified, something like Article II was added to the Constitution as the Tenth Amendment. Unfortunately it is like Article II in the same sense that a whale is like a fish—superficially.
The Tenth Amendment says: “The powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people.”