Presidential succession explained: Who becomes Vice President if the President dies and what if neither can serve?

THE US Constitution has measures in place to make sure there is someone leading the country should a president die.

Here we explain what would happen if such an event took place.

What happens if a presidential candidate dies before the election? 

The death of a presidential candidate would not halt the election.

Instead, a new candidate would be selected.

Both the Democratic National Committee (DNC) and the Republican National Committee (RNC) have processes by which they can replace the deceased nominee with a majority vote.

The VP nominee, however, would be the easiest choice to replace the deceased, as their name would already be on the ballot.

If they choose to fill the vacancy with a completely new candidate, they will have to go through the process the same way a presidential candidate is selected during the national convention - but do it before the Electoral College votes in December.

RNC members would cast their votes and the candidate would be elected by a majority.

The RNC must re-elect their new presidential candidate so it would not automatically fall to the vice president.

The vice president would constitutionally be required to fill the role of president in the interim period.

The Democratic National Committee (DNC) has similar rules - its members would choose the new candidate after the DNC chair consulted with the party's leaders in Congress and with its state governors.

The selected candidate's name would then be placed on the ballot papers and the election would continue as normal.

What happens if a candidate dies after the popular vote?

In the US election, the public doesn’t directly elect the president.

They vote for members of the Electoral College in their state, and the Electoral College then selects the president.

The Electoral College does not vote until December – over a month after the election.

If a candidate dies between the election and the Electoral College voting, the process is the same as before, in that the party selects a replacement candidate.

The party would expect their electors to still vote for their new candidate, but they are not required to by law – they could vote for another member of their party or even a third-party candidate if they wished.

What if the president-elect dies before being inaugurated?

Congress counts the Electoral College votes in January.

Should a winning candidate die between December after the vote, but before January's count of the votes, things start to get messy.

Congress would have to decide whether to count the votes for the dead candidate.

But if it did, then the vice president-elect would become the president.

If it decides not to count the vote, the 12th Amendment states the House of Representatives must elect the president from the three candidates with the most votes.

Effectively this means in a two-horse race, the living candidates become president.

Finally, if the president-elect were to die after Congress has counted the votes on January 6, the rules of succession would almost certainly apply.

This means the vice-president elect would become president.

Who becomes Vice President if the President dies? 

The new president appoints someone to fill his or her old position.

This is subject to congressional approval.

The 25th Amendment states: “Whenever there is a vacancy in the office of the Vice President, the President shall nominate a Vice President who shall take office upon confirmation by a majority vote of both Houses of Congress."

What happens if the president and vice president die? 

In a scenario where both the President and Vice President were to die, the constitution also lays down a line of succession. 

The Presidential Succession Act of 1947 states that if both the President and Vice President were to die then the US House of Representatives Speaker would take over as commander-in-chief of the United States.