What determined the order in which the cabinet members would succed to the office of president?

The order of succession for the presidency is determined by the Presidential Succession Act of 1947, which establishes a clear line of succession beyond the vice president. This act outlines that cabinet members would succeed the presidency based on the chronological order in which their respective departments were created, starting with the Secretary of State. Subsequent cabinet members follow in the order of their department's establishment, ensuring a structured transition of power in the event of vacancies.