What action can Congress take if the president vetoes a bill?

Congress has the constitutional authority to override a presidential veto with a two-thirds majority vote in both the House of Representatives and the Senate. This action is significant because it allows Congress to reaffirm its legislative decisions even when the president opposes them. The ability to override a veto demonstrates the system of checks and balances established in the Constitution, ensuring that no single branch of government has absolute power over legislation.

In contrast, rewriting the bill is not a direct action taken in response to a veto but rather an option for Congress to consider if they wish to address the president's concerns before resubmission. Sending the bill to the Supreme Court does not apply, as the Court does not have the authority to adjudicate legislative matters before they are enacted. Initiating a filibuster is a tactic within the Senate to delay or prevent a vote on a bill but does not relate to overcoming a presidential veto.