Checks and Balances in Judicial Appointments

In the context of the United States government, the Constitution establishes a system of checks and balances through the separation of powers among the three branches: the legislative, the executive, and the judicial. This mechanism is designed to prevent the concentration of power in any single branch and ensure that each branch can restrain the other two. Consider the following scenario: A president nominates a candidate to the Supreme Court, and this nomination is ultimately rejected by the Senate.

Which of the following concepts best explains the political dynamics seen in this situation?