From 1782 to 1795, Marshall was repeatedly elected to the Virginia Legislature, the last time without his knowledge and against his wishes; and he also served one term as a member of the Executive Council of the State; but, as his residence was for the most part at Richmond, his public service did not seriously interrupt his career at the Bar.  His experience in State politics, however, served to deepen his conviction of the need of an efficient and well-organized national government and of restrictions on the power of the States.

In the formation of the Constitution of the United States Marshall had no hand; he was not a member of the convention by which it was framed; but when it was submitted to the several States for their action, he became a determined advocate of its adoption.  In the Virginia convention, which was called to act upon that question, the prospects of a favorable decision seemed at first to be most unpromising.  Among those who opposed ratification we find the names of Henry, Mason, Grayson, and Monroe, names which sufficiently attest that the opposition was one, not of mere faction or obstruction, but of principle and patriotic feeling.  Henry, who had been one of the first in earlier days to sound the note of revolution, saw in the proposed national government a portent to popular liberties.  In the office of President he perceived “the likeness of a kingly crown.”  In the control of the purse and the sword, he foresaw the extinction of freedom.  In the power to make treaties, to regulate commerce, and to adopt laws, he discerned an “ambuscade” in which the rights of the States and of the people would be destroyed unawares.  To these alarming predictions the advocates of ratification replied with strong and temperate reasoning, and, while Madison was their leader, among those who won distinction in the contest stood Marshall.  He argued that the plan adopted by the Federal Convention provided for a “regulated democracy,” the only alternative to which was despotism.  He contended for the establishment of an efficient government as the only means of assuring popular rights and the preservation of the public faith, violations of which were constantly occurring under the existing government.  It is interesting to notice that, in replying to the suggestion that the legislative power of the proposed government would prove to be practically unlimited, he declared:  “If they [the United States] were to make a law not warranted by any of the powers enumerated, it would be considered by the judges as an infringement of the Constitution, which they are to guard against....  They would declare it void.”  In the end the Convention ratified the Constitution by a majority of ten votes, a result probably influenced by the circumstance that it had then been accepted by nine States, and had thus by its terms been established between the adhering commonwealths.