A presidential election is an election in which citizens of a country or territory choose their head of state, who is usually also the head of government. The president is the highest executive office in a country, and the president's powers and responsibilities vary from one country to another. In most countries, the president is the leader of the government and the head of the executive branch of government. In some countries, the president is also the head of the military or holds other important positions of power. In general, the president is responsible for enforcing the laws of the country, negotiating treaties and agreements with other countries, and representing the country on the international stage. Presidential elections are typically held every four or five years, although the exact timing can vary depending on the country.