In 1819, he delivered in the case of McCulloch v.  Maryland what is generally regarded as his greatest and most carefully reasoned opinion.  The particular questions involved were those (1) of the power of the United States to incorporate a bank, and (2) of the freedom of a bank so incorporated from State taxation or control.  The United States bank, which Congress had rechartered in 1816, had established a branch in Maryland.  Soon afterwards the Legislature passed an Act requiring all banks situated in the State to issue their notes on stamped paper, the object being to strike at the branch bank by indirectly taxing it.  The case was ’argued before the Supreme Court by the most eminent lawyers of the day, Pinkney, Webster, and Wirt appearing for the bank, and Luther Martin, Joseph Hopkinson, and Walter Jones for the State of Maryland.  The unanimous opinion of the court was delivered by Marshall.  It asserted not only the power of the Federal government to incorporate a bank, but also the freedom of such a bank from the taxation, control, or obstruction of any State.  While no express power of incorporation was given by the Constitution, yet it was found to be a power necessarily implied, since it was essential to the accomplishment of the objects of the Union.  This principle Marshall laid down in these memorable words:  “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.”

Of no less importance than the opinions heretofore mentioned are those that deal with the power of the general government to regulate commerce and to preserve it from hindrance on the part of the States.  Of these the chief example is that which was delivered in the case of Gibbons v.  Ogden, in 1824.  By the Legislature of New York an exclusive right had been granted to Chancellor Livingston and Robert Fulton for a term of years to navigate the waters of the State with steam.  The validity of this statute had been maintained by the judges in New York, including Chancellor Kent, and an injunction had been issued restraining other persons from running steamboats between Elizabethtown, New Jersey, and the city of New York, although they were enrolled and licensed as coasting vessels under the laws of the United States.  The Supreme Court, speaking through Marshall, held the New York statute to be unconstitutional.  By the Constitution of the United States, Congress is invested with power “to regulate commerce with foreign nations and among the several States.”  The term “commerce” Marshall declared to embrace all the various forms of intercourse, including navigation, and he affirmed that “wherever commerce among the States goes, the judicial power of the United States goes to protect it from invasion by State legislatures.”