It might be objected that because the States ratified the Constitution, the people can delegate power only through the States or by acting in their capacities as citizens of particular States. See post, at 2-3. But in
McCulloch v. Maryland [1819], the Court set forth its authoritative rejection of this idea:
"The Convention which framed the constitution was indeed elected by the State legislatures. But the instrument . . . was submitted to the people. . . . It is true, they assembled in their several States--and where else should they have assembled? No political dreamer was ever wild enough to think of breaking down the lines which separate the States, and of compounding the American people into one common mass. Of consequence, when they act, they act in their States. But the measures they adopt do not, on that account, cease to be the measures of the people themselves, or become the measures of the State governments." 4 Wheat., at 403.
The political identity of the entire people of the Union is reinforced by the proposition, which I take to be beyond dispute, that, though limited as to its objects, the National Government is and must be controlled by the people without collateral interference by the States.
McCulloch affirmed this proposition as well, when the Court rejected the suggestion that States could interfere with federal powers. "This was not intended by the American people. They did not design to make their government dependent on the States." Id., at 432. The States have no power, reserved or otherwise, over the exercise of federal authority within its proper sphere.
There can be no doubt, if we are to respect the republican origins of the Nation and preserve its federal character, that there exists a federal right of citizenship, a relationship between the people of the Nation and their National Government, with which the States may not interfere.
http://www.law.cornell.edu/supct/html/93-1456.ZC.html