An opposition party is a political party that is not in power and actively challenges the policies and decisions of the ruling government. Its main role is to represent alternative viewpoints and hold the government accountable for its actions. Opposition parties often propose their own policies and seek to gain public support to win future elections. In many democratic systems, such as those found in the United States or the United Kingdom, opposition parties play a crucial role in the political process. They participate in debates, question government officials, and provide checks and balances to ensure that the ruling party does not abuse its power.