Argentina (officially The Argentine Republic) is a federal republic with a bicameral congress. The National Congress is composed of the Senate and the Chamber of Deputies. Each of the 23 provinces (and the autonomous federal capital, Buenos Aires) elects senators for the Senate. The representatives of the Chamber of Deputies are elected by congressional districts based on proportional representation. Legislative proposals are called law projects and are generally introduced in the Chamber of Deputies before debate and vote in the Senate. To become law, all bills must be passed by both congressional bodies and signed by the President, who acts as both head of state and head of government.
A law project is first drafted, proposed and debated in legislative committees in the Chamber of Deputies. Often included in the committee debate is expert testimony. Once the proposal has passed the relevant legislative committee, it is officially presented and debated by all deputies, and amendments may be considered. Once passed by both chambers of Congress, the President promulgates, vetoes or partially vetoes the legislation within 10 working days. A presidential veto can be overridden with a two-thirds majority in both chambers of Congress.