Final answer:
The only other nationally elected leader in the United States besides the president is the A. Vice President. The Speaker of the House and the Supreme Court Justices, while prominent, are not elected by the national populace.
Step-by-step explanation:
Besides the President of the United States, the only other nationally elected leader in the United States is the Vice President. This is due to both positions being filled through the electoral process involving the Electoral College, where electors are chosen by the people in each state to vote for the presidential ticket. The President and Vice President are the only executive officials elected on a nationwide basis. The Vice President assumes office alongside the president and can take over the presidency if the president is unable to continue their duties.
Other significant figures, such as the Speaker of the House and Justices of the Supreme Court, are selected through different processes. The Speaker of the House is elected by members of the House of Representatives, while Supreme Court Justices are nominated by the president and confirmed by the Senate. These positions are not decided through national elections by the general public.
The 25th Amendment provides a method for filling a vacancy in the Vice Presidential position. The sitting president can nominate a candidate who then must be confirmed by a majority vote in both the House and the Senate.