Under the system of Check and Balances, each branch of the government has the power to oversee, limit and check the other. The President, for example, who is head of the Executive Branch, has the power to reject bills proposed and passed by Congress: When Congress passes a bill, it has to send it to the President for signature. However, the President may decide to use his or her veto power and to reject the bill; if this happens, the bill is sent back to Congress, which has the power to override the Presidential veto only if 2/3 of the Congress members vote in favor of the proposed bill.
The closest one is the first one. He can veto any bill and send it back to congress. He has to state why and they have to consider his whys. If both houses can must a 2/3 majority for the bill, it passes without his signature.
