Should Congress, in the execution of its powers, adopt measures which are prohibited by the constitution; or should Congress, under the pretext of ex… - John Marshall

We admit, as all must admit, that the powers of the Government are limited, and that its limits are not to be transcended. But we think the sound construction of the Constitution must allow to the national legislature that discretion with respect to the means by which the powers it confers are to be carried into execution which will enable that body to perform the high duties assigned to it in the manner most beneficial to the people. Let the end be legitimate, let it be within the scope of the constitution, and all means which are appropriate, which are plainly adapted to that end, which are not prohibited, but consist with the letter and spirit of the constitution, are constitutional.

It is emphatically the province and duty of the Judicial Department to say what the law is.

The convention which framed the Constitution was indeed elected by the State legislatures. But the instrument, when it came from their hands, was a mere proposal, without obligation or pretensions to it. It was reported to the then existing Congress of the United States with a request that it might "be submitted to a convention of delegates, chosen in each State by the people thereof, under the recommendation of its legislature, for their assent and ratification." This mode of proceeding was adopted, and by the convention, by Congress, and by the State legislatures, the instrument was submitted to the people. They acted upon it in the only manner in which they can act safely, effectively and wisely, on such a subject — by assembling in convention. 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. From these conventions the Constitution derives its whole authority. The government proceeds directly from the people; is "ordained and established" in the name of the people, and is declared to be ordained, "in order to form a more perfect union, establish justice, insure domestic tranquillity, and secure the blessings of liberty to themselves and to their posterity." The assent of the States in their sovereign capacity is implied in calling a convention, and thus submitting that instrument to the people. But the people were at perfect liberty to accept or reject it, and their act was final. It required not the affirmance, and could not be negatived, by the State Governments. The Constitution, when thus adopted, was of complete obligation, and bound the State sovereignties.