What is required for Congress to override a presidential veto?

To override a presidential veto, Congress needs a 2/3 vote in both the House of Representatives and the Senate. This requirement is significant as it reflects the framers' intent to ensure that overriding a presidential decision is a deliberate and substantial action, requiring broad support within the legislature.

The rationale behind this threshold is to maintain a system of checks and balances between the executive and legislative branches. A simple majority would allow for oversights or momentary shifts in opinion to easily overturn a presidential decision, which may not reflect the considered judgment of Congress as a whole. Similarly, a unanimous vote or a 3/4 vote would be excessively high benchmarks, likely making it nearly impossible to successfully override a veto. Thus, the 2/3 vote strikes a balance, allowing Congress to assert its authority while also maintaining a safeguard against impulsive actions.