How can Congress override a presidential veto?

To override a presidential veto, Congress must achieve a two-thirds majority vote in both the House of Representatives and the Senate. This process is established in the U.S. Constitution, which grants Congress the power to check the President's authority by allowing them to overturn a vetoed bill.

The requirement for a two-thirds majority ensures that a substantial consensus is needed among lawmakers to counter the President's decision, reflecting the seriousness of overriding an executive veto. It serves as a balance of power mechanism within the federal government, demonstrating how the legislative branch can assert its authority when it believes legislation is critical for the public interest, despite the President’s objections.

The other options listed do not meet the constitutional requirements for overriding a veto, making them invalid. A simple majority in one house, for example, is insufficient, as a veto override requires agreement from both chambers. Similarly, a unanimous vote or a four-fifths majority would exceed the constitutional stipulations and is therefore not a viable means of overcoming a presidential veto.