The case of Marbury v. Madison impacted the United States by giving the Supreme Court much more power in our political system. This eventually led to some major events in US history.
Before Marbury it was not clear that the Supreme Court could say that laws passed by Congress were unconstitutional. In Marbury, the Court declared that it had that power, which we call the power of judicial review. This did not change the US right away. However, the Supreme Court eventually started using this power in ways that did change the country.
When the Supreme Court started using the power of judicial review, it had some major impacts on the country. For example, the Dred Scott decision overturned the Missouri Compromise. This meant that political compromise between the North and South would be harder to come by. Eventually, this decision helped to start the Civil War.
Later on, in 1896, the Supreme Court decided the case of Plessy v. Ferguson. In that case, it decided that the Constitution allowed white-run governments to discriminate against African Americans and to impose segregation on them. This continued until the Court made another tremendously important decision in Brown v. Board of Education in 1954. Then, the Court banned segregation, making it possible for us to get closer to true racial equality.
We can still see the Court’s power today. It decided that abortion was a right in Roe v. Wade. It recently decided that there is a right to same-sex marriage. If it were not for the ruling in Marbury, these changes might not have occurred in our country. Therefore, this case impacted the US by giving the Supreme Court a great deal of power to shape our society.