If the President can no longer serve, who becomes President?

The Vice-President assumes the presidency if the sitting President can no longer serve, whether due to resignation, death, removal, or incapacitation. This line of succession is established by the Presidential Succession Act and further reinforced by the 25th Amendment to the U.S. Constitution. The amendment outlines the procedures for filling a vacancy in the office of the President and clarifies that the Vice-President is next in line to take over the presidency.

The other roles mentioned, such as the Secretary of State, the Speaker of the House, and the Chief Justice, do not directly succeed the presidency unless the line of succession involves more than just the Vice-President and is initiated further down the line. In a direct scenario where the President can no longer fulfill their duties, the Vice-President is the immediate successor.