The main duties of a senator in the United States include crafting legislation, representing constituents, and providing oversight of the executive branch. Senators participate in shaping federal laws by proposing bills, debating measures, and conducting votes. They serve as advocates for their states, ensuring constituents' needs and interests are addressed in Washington. Additionally, senators play a critical role in confirming presidential appointments and ratifying treaties. Through committee work, senators also oversee governmental agencies to ensure accountability and transparency. Collectively, these responsibilities highlight the multifaceted role senators play in the American political system.