If both the President and the Vice President can no longer serve, who becomes President?

If both the President and the Vice President of the United States are unable to serve, the next in line is the Speaker of the House of Representatives. This order of succession is established by the Presidential Succession Act of 1947.

After the Speaker of the House, the next in line is the President pro tempore of the Senate (who is traditionally the longest-serving member of the majority party), followed by the members of the Cabinet, starting with the Secretary of State.

It's important to note that any person succeeding to the presidency must be eligible to serve as President under the Constitution, meaning they must be a natural-born U.S. citizen, at least 35 years old, and have lived in the U.S. for at least 14 years.