by saying that the law was constitutional. 

In Marbury, the Supreme Court declared that a law passed by Congress (the Judiciary Act of 1789) was unconstitutional and it therefore said that the law could not be enforced.  This was extremely important in our history because it established that the Court could overrule acts of Congress that were unconstitutional.  This has had an immense impact on our history because it has allowed the Supreme Court to rule on laws that have had to do with everything from the price of hauling freight on railroads to child labor to abortion.  This has made the Supreme Court an important player in our history.

The 1803 case Marbury v. Madison is one of the landmark decisions under John Marshall because it established the power of the judicial branch with the principle that the Supreme Court may declare an act of Congress void if it is inconsistent with the United States Constitution. This means the Court has the power to decide which laws are constitutional in what is known a judicial review.

Here is the history of this case:

The outgoing President, John Adams, who was anxious about losing positions from his political party, nominated forty-two judges prior to his leaving office so that his party's majority could out-rule the incoming President, Thomas Jefferson. One of the nominated judges was William Marbury.

When the last-minute commissions were not completely processed before Adams left office, Marbury was simply appointed as a judge. When Jefferson came into office, the judges' positions were reduced in number, leading Marbury to lose his job as part of this reduction. Marbury then submitted a grievance, asking the new Secretary of State, James Madison, to award him his position as justice of the peace for Washington County in the District of Columbia. When Madison denied Marbury his position in the court, Marbury subsequently petitioned for a writ of mandamus compelling delivery of the commissions.

Writing for a unanimous court, Chief Justice John Marshall thought that Secretary of State Madison was wrong for having denied Marbury his position; however, according to the U.S. Constitution, Marshall wrote, the Supreme Court did not have the power to issue such writs of mandamus. 

Marshall determined that Section 13 of the Judiciary Act of 1789—authorizing the Supreme Court to issue writs to government officials—was unconstitutional because it was an extension of judiciary power into the realm of the executive.

Since the judiciary’s first responsibility is to uphold the Constitution at all times, Marshall wrote that if two laws conflict, the court bears responsibility for deciding which law applies in any given case. This decision in Marbury v. Madison, then, established what is known as judicial review. That is, the Supreme Court has the power to decide which laws are constitutional. In establishing judicial review, the decision of Marbury v. Madison has had a profound impact on American history.

Marbury v. Madison is important because this was the case in which the Supreme Court of the United States declared that it had the power of judicial review.

The Constitution says that it is the supreme law of the land.  No law may be passed that violates the Constitution.  But who gets to decide which laws violate the Constitution?  The Constitution does not say.  In this case, the Supreme Court decided that they are the ones who get to decide on this issue (this is what “judicial review” means).  So, this case is important because it led to the establishment of one of the most important parts of our political system. 

The landmark Supreme Court case of Marbury v Madison (1803) established the Supreme Court as a major player in the American political system.

Prior to the case, the Supreme Court had been very much the junior partner among the three branches, with the executive (the presidency) and the legislative (Congress) branches enjoying considerably more power and prestige.

But Marbury changed all that. For the first time, the Supreme Court arrogated to itself the power of judicial review—the power to strike down government actions and legislative acts as unconstitutional. From that day forth, the Supreme Court has played an increasingly important role in the American system of government, regularly becoming embroiled in such contentious political issues as abortion, civil rights, and the rights of workers.

The irony of Marbury is that it involved the Court actually rejecting specific powers that had been granted to it by an act of Congress. Congress had authorized the Supreme Court to deal with cases such as those involving the plaintiff, Marbury. But the Court argued that in bestowing this power on the judicial branch, Congress was exceeding its authority. So the relevant act of Congress giving the Supreme Court the power to deal with cases such as Marbury was therefore unconstitutional.

In striking down a piece of legislation that had actually given it more power, the Supreme Court was awarding itself the much bigger power of judicial review, a power that it has used regularly ever since. And it is largely on the basis of this power that the Supreme Court continues to play an important role in the American political system.