Under Chief Justice Marshall, the US Supreme Court became a major player in American government for the first time, far more important than anyone could possibly have envisaged. After arrogating to itself the power of judicial review in Marbury v Madison (1803) the Court came to occupy a central position in American civic life, one it has yet to relinquish to this day.

The overall jurisprudence of the Marshall Court can be seen as closely aligning with the Federalist agenda, complete with a more flexible interpretation of the Constitution. Not surprisingly, Jefferson and other leading Republicans looked upon the judiciary as a Federalist bastion, attempting to achieve through the courts what they palpably failed to do in the 1800 Presidential election. Despite the conspiratorial tenor of the Republicans' political rhetoric there was more than a grain a truth in their suspicions. Marshall had, after all, been appointed by President Adams, who described him as his "gift" to the American people, and was himself a staunch Federalist.

Right throughout the lengthy course of his Chief Justiceship, Marshall put his Federalist principles into action, giving judicial force to the principle of a strong federal government asserting its supremacy over the states. Under Chief Justice Marshall, a state law was struck down as unconstitutional for the very first time, in the case of Fletcher v Peck (1810).

As part of their desire to build a strong federal government, the Federalists advocated the establishment of a central bank. This position was further consolidated at the judicial level in McCulloch v Maryland (1819) in which the Court held that attempts by the Maryland state legislature to impose a tax upon a branch of the Second Bank of the United States were unconstitutional.

The Marshall Court also proved itself to be a redoubtable defender of the Union against the remotest possible threat of secession. In Cohens v Virginia (1821) a relatively trivial criminal case regarding the legality of a federal lottery metamorphosed into a full-blown clash between the advocates of states' rights and Federalism. The General Assembly of Virginia rose in fury, not just denying the Supreme Court's jurisdiction in the case, but even making not so veiled threats to secede from the Union.

Despite the growing threats and anger from the Southern states Marshall stood firm, affirming once again the supremacy of Federal over state law. This principle, combined with the establishment of judicial review is undoubtedly the Court's greatest legacy. Yet in the long run such a bald assertion of centralized power did nothing to quell the growing tensions between federal and state governments that would come to a tragic head forty years later.

One of the most profound impacts of the Marshall Court was in its emphasis of the Supreme Court's power in Marbury v. Madison.

Prior to the Marshall Court, framers of the Constitution like Alexander Hamilton considered the Supreme Court part of the least important branch of government.  The Marshall Court changed this perception in Marbury v. Madison.  The case's critical issue was whether the court had the power to assert a constitutional check on other branches of government.  The Marshall Court argued that the Supreme Court has the power to constitutionally limit the legislative branch and even the President.  Marshall argued that the Supreme Court's "obligation" was  "to uphold the Constitution because, by Article VI, it is the "supreme law of the land." 

Through its decision of Marbury v. Madison, the Marshall Court established the idea of judicial review. This meant that only the judicial branch could review whether laws and actions were constitutional.  The Marshall Court affirmed the power of the Supreme Court.  It had the ability to interpret the Constitution and could use it to determine the validity of the other two branches' actions.  The Marshall Court transformed how the Supreme Court was seen.  In doing so, the Marshall Court had a profound impact on American government.

The Marshall court had a significant impact on the federal government. As a result of several decisions, the power of the federal government grew significantly.

The court case of McCulloch v Maryland was very important for the federal government. Maryland had taxed the federal bank. The bank refused to pay this tax saying that a state can’t tax a federal institution such as the bank. The Supreme Court ruled that Maryland was wrong in taxing the bank. The bank didn’t have to pay the tax. More importantly, the Supreme Court said that a loose interpretation of the Constitution was legal. This gave the federal government the power to do things that aren’t specifically stated in the Constitution.

Another case that increased the power of the federal government was Gibbons v Ogden. In this case, the Supreme Court ruled that the federal government controlled interstate trade. This gave the government more power in dealing with trade between the states.

The impact of the Marshall Court was very positive for the federal government. This court increased the power of the federal government.