If both the president and the vice president can no longer serve, who becomes president?

The Speaker of the House becomes president if both the president and the vice president are unable to serve. This succession is outlined in the Presidential Succession Act of 1947, which establishes the order of succession to the presidency. The Speaker is the leader of the House of Representatives and is next in line after the vice president. This structure ensures continuity of government leadership and is essential for maintaining stability during times of crisis or transition. The Secretary of State, President pro tempore, and Majority Leader of the Senate do not hold the same authority or role in the line of succession as the Speaker of the House, making the Speaker's position pivotal in ensuring a smooth transition of power in such circumstances.