Final answer:
Judicial review ensures a balance of power in the United States by checking the constitutionality of laws.
Step-by-step explanation:
Judicial review ensures a balance of power in the United States by checking the constitutionality of laws. It is the power of the courts to review and overturn laws or actions of the legislative and executive branches based on their constitutionality. By determining whether laws are in agreement with the Constitution, the courts can ensure that the other branches are not exceeding their authority. This reinforces the system of checks and balances and helps maintain a balance of power in the country.