Which institution or institutions is/are most directly responsible for enforcing the Constitution's limits on government power?

Question

Quizplus · Accepted Answer

Federal courts, specifically the Supreme Court, are responsible for interpreting and enforcing the Constitution's limits on government power through their power of judicial review. Congress and the president have their own specific roles in the government, but they are not solely responsible for enforcing constitutional limits on government power. The states have some power to challenge federal actions, but it is ultimately up to the federal courts to interpret and enforce the Constitution. The United Nations is not a relevant institution in enforcing the Constitution's limits on government power as it is an international organization separate from the US government.

Which Institution or Institutions Is/are Most Directly Responsible for Enforcing