In so doing, Marshall contributed to sorting out the boundaries of the three branches of the federal government, in the separation-of-powers and checks-and-balances systems established by the Constitution.
The Constitution also addressed the issue of the balance of power between the federal government and the states, and Marshall subsequently weighed in on that question.
The political history of the United States has involved, for better or worse, an almost continuous movement toward stronger central government. From the Continental Congresses, to the Constitution of 1787, to the post-Civil War constitutional amendments, to the Supreme Court's belated acceptance of New Deal federal activism, every major move has been in the direction of centralization.
Certain decisions of the Marshall Court in the early 19th century contributed to that trend. One such case is McCulloch v. Maryland, in 1819.
Congress chartered the Bank of the United States, in 1816, and James McCulloch headed up a branch of that bank in Baltimore. The state of Maryland did not take kindly to the imposition of an outside bank within its boundaries. Maryland imposed a tax on operations of the bank, and then sued McCulloch when he refused to pay.
The Supreme Court struck down the state tax, in a decision that set two important precedents:
The first involves the Court's defense of Congress's authority to charter the Bank. Article I, Section 9 of the Constitution lists several specific powers allocated to Congress. The Constitutional Convention placed at the end of that list, a paragraph that is sometimes called the "Elastic Clause", which empowers Congress:
To make all Laws which shall be necessary and proper for carrying into Execution the foregoing Powers and all other Powers vested by this Constitution in the Government of the United States, or in any Department or Officer thereof.
The Court interpreted that clause to give Congress the power to take actions not specifically described in that section. While chartering a bank was not specifically allowed, such an action was "necessary and proper for carrying into Execution the" powers to tax and spend.
The second precedent prohibited states from interfering in the operations of the federal government.
Article VI, clause 2 of the Constitution provides that:
This Constitution, and the Laws of the United States which shall be made in Pursuance thereof; and all Treaties made, or which shall be made, under the Authority of the United States, shall be the supreme Law of the Land; and the Judges in every State shall be bound thereby, any Thing in the Constitution or Laws of any state to the Contrary notwithstanding.
The Court found that Maryland's tax constituted an assertion of supremacy over the federal government. In a case such as this where, in the Court's opinion, the federal government had properly acted within its constitutional authority, federal law trumps state law.