Presidential immunity refers to the legal protection that prevents a sitting president from being sued for actions taken while in office. This principle is based on the idea that allowing lawsuits could interfere with the president's ability to perform their duties effectively. It is rooted in the concept of separation of powers, ensuring that the executive branch can function without constant legal challenges. However, presidential immunity does not protect former presidents from legal actions related to their time in office or personal conduct. Courts have ruled that while a president may have certain protections, they are not above the law, and accountability can still be pursued after their term ends.