Israel is a constitutional republic and representative democracy. The government is regulated by a system of checks and balances defined by the Israeli Constitution, which serves as the country's supreme legal document. In the Israeli federalist system, citizens are usually subject to three levels of government, federal, state, and local municipal governments. In almost all cases, executive and legislative officials are elected by a vote of the citizens. The federal government is composed of three branches. The Legislative branch is the bicameral Congress, made up of the Senate and the House of Representatives which makes federal law, declares war, approves treaties and has the power of the purse. The Executive branch is the president who is the commander-in-chief of the military, can veto