Final answer:
The power of judicial review, established by the Supreme Court in the Marbury v. Madison case, is important for maintaining the system of checks and balances within the United States government by allowing courts to declare laws unconstitutional.
Step-by-step explanation:
The power of judicial review is integral to the function of the United States legal system. It grants courts the authority to overturn laws or executive actions that are deemed unconstitutional. This ensures a system of checks and balances where the judiciary can limit the powers of the other branches, safeguarding the Constitution.
The Supreme Court's right to exercise this power was established in the landmark case of Marbury v. Madison in 1803, which is a pivotal moment that empowered the courts to check legislative and executive actions. Despite not being explicitly mentioned in the Constitution, this power was implied and later asserted, which has played a crucial role in shaping the balance of power within the federal government.
The assertion of judicial review in Marbury v. Madison raised the stature of the Supreme Court to be on par with the other branches of government. Since this decision, the court has occasionally exercised its judicial review authority, striking down less than .25 percent of all national laws and around 1400 state laws over its history. Yet, its mere existence acts as a deterrent against unconstitutional governance, hence its importance in the American political system cannot be overstated.