The President of the United States of America has a veto, power which means that he can veto a bill passed by the Congress, preventing it from becoming law unless each house then re-passes the bill by a two-thirds majority. The veto power vested in the President by Article I, Section 7 of the Constitution has proved to be an effective tool for the Chief Executive in his dealings with Congress. The most important of all the checks and balances of the United States of America Constitution is, of course, the presidential veto.