Short Answer 
The concept of judicial review, established in *Marbury v. Madison*, empowers the Supreme Court to interpret laws and assess their constitutionality. Chief Justice John Marshall’s 1803 ruling determined that certain provisions of the Judiciary Act of 1789 were unconstitutional, reinforcing the Court’s authority to check the legislative and executive branches and maintain balance within the government.
Step 1: Understanding Judicial Review
The cornerstone of the ruling in *Marbury v. Madison* is the concept of judicial review. This is the power granted to the Supreme Court to interpret laws and determine their constitutionality. The establishment of this principle allows the Court to invalidate any legislative or executive actions that are found to conflict with the Constitution. This foundational principle was introduced during the early 19th century, setting essential legal precedents for future cases.
Step 2: Chief Justice Marshall’s Decision
Chief Justice John Marshall played a pivotal role in establishing judicial review through this landmark case. In the 1803 ruling, he concluded that Section 13 of the Judiciary Act of 1789 was unconstitutional, as it attempted to expand the Court’s original jurisdiction. This decision reinforced the principle that the Supreme Court had the authority to review and nullify laws that contradicted the Constitution, which was significant for upholding the rule of law in the United States.
Step 3: Impact on Government Balance
The ruling in *Marbury v. Madison* drastically changed the relationship between the branches of government. By asserting the power of judicial review, the Supreme Court positioned itself as a check on the legislative and executive branches. This function is crucial because it maintains a balance of power, ensuring that no branch exceeds its authority; hence, it has far-reaching implications for American democracy and governance.