Congress can override a presidential veto by passing the bill again with a two-thirds majority vote in both the House of Representatives and the Senate. This means at least 290 out of 435 representatives and 67 out of 100 senators must vote in favor of overriding the veto for the bill to become law despite the president's objections

. The process begins when the president returns the vetoed bill to the chamber where it originated, along with a message explaining the reasons for the veto. That chamber then enters the veto message into its official record and proceeds to reconsider the bill. If the chamber of origin votes to override the veto by a two-thirds majority, the bill is sent to the other chamber for a similar vote. Only if both chambers successfully override the veto does the bill become law

. This override mechanism is a constitutional check on presidential power, outlined in Article 1, Section 7 of the U.S. Constitution, ensuring that Congress can enact legislation even if the president objects, provided there is substantial congressional support

. In summary, the key steps are:

• President vetoes a bill and returns it with objections.
• The originating chamber records the veto message and votes on reconsideration.
• If two-thirds of that chamber vote to override, the bill goes to the other chamber.
• The other chamber also votes, requiring a two-thirds majority to override.
• If both chambers achieve this supermajority, the veto is overridden and the bill becomes law