What is one responsibility that is uniquely assigned to United States citizens?

The responsibility that is uniquely assigned to United States citizens is to vote in a federal election. Voting is a fundamental right and civic duty that differentiates citizens from non-citizens. It allows citizens to participate actively in the democratic process, influencing legislation and selecting leaders at various levels of government. While residents, including non-citizens, may fulfill other responsibilities such as paying taxes or attending school, the legal right to vote is specifically granted to citizens, emphasizing their role in shaping the government and its policies. This civic engagement through voting is crucial to the functioning of democracy in the United States.