The role of a head of state and a head of government can vary significantly depending on the political system. The head of state often symbolizes the unity and integrity of the nation, fulfilling ceremonial roles, while the head of government is responsible for running the day-to-day affairs of the state and implementing policies. For instance, in parliamentary systems, the head of government, typically the prime minister, plays a more direct role in governance, while the monarch or president serves as a ceremonial figurehead. In contrast, in presidential systems, the roles may be combined, as seen in the United States.