Americans are bracing for a rare presidential rematch between the two oldest candidates in US history: the 81-year-old president Joe Biden and the 77-year-old former president Donald Trump.
Concerns about their age, mental fitness and the possibility that Trump could be convicted of a felony and sentenced to prison time before election day have raised questions about what would happen in the extraordinary event that one of them dies, becomes incapacitated or abruptly withdraws.
If Biden, as the sitting president, were to die the vice-president, Kamala Harris, would assume the powers of the presidency under the 25th amendment. But replacing Biden or Trump as their party’s presumptive nominees for president – a prospect that is entirely hypothetical – is more complicated. In the event of an unforeseen vacancy, party rules, state and federal election laws and the US constitution would guide what would undoubtedly be a messy process.
What happens if Biden or Trump needs to be replaced?
The answer, experts say, depends largely on when the vacancy arises. Is it after the party’s nominating convention? Before election day? What if the winning candidate is no longer able to take the oath of office? The timing matters.
If the unexpected occurs, the job of replacing the presidential candidate would fall to “10,000 people who no one has ever heard of”, according to Elaine Kamarck, a member of the Democratic National Committee rules committee and a senior fellow at the Brookings Institution. Collectively they represent convention delegates, members of the parties’ national committees, the 538 members of the electoral college and the 435 members of the House of Representatives.
Each plays a relevant role at different stages of the election process.
What if it happens before a party’s convention?
Biden and Trump have secured enough delegates to be their parties’ nominee in mid-March, but neither will be formally selected until the conventions this summer. The Republican national convention will take place in Milwaukee in mid-July. The Democratic convention will take place a month later in Chicago.
Before then, state parties will continue to hold primaries, caucuses and conventions, electing delegates to send to conventions.
If Biden or Trump were to withdraw or die before being formally nominated, their delegates would arrive at the convention in Milwaukee or Chicago largely uncommitted. A replacement nominee would then probably be chosen at the convention in a messy floor fight. Imagine frantic horse-trading, back-room dealing and public speech-making.
Democrats also have a system of “superdelegates” – unpledged senior party officials and elected leaders whose support is limited on the first ballot but who could play a decisive role in subsequent rounds.
Would the running mate automatically move to the top of the ticket?
The short answer is no. Neither Harris, nor Trump’s eventual vice-presidential pick, would automatically become the nominee, according to DNC and RNC rules.
But delegates tend to be people with a degree of loyalty to the candidate or party. So in all likelihood, the running mate would emerge as a strong contender for the nomination.
Presumably a Biden delegate would be open to supporting Harris, who, in the event Biden has died or fallen critically ill, would already be serving as president. Nevertheless, if a vacancy emerges, it is possible alternative candidates would step forward – imagine the California governor, Gavin Newsom, or his Michigan counterpart, Gretchen Whitmer.
On the Republican side, Trump has yet to choose a running mate. The runner-up for the Republican nomination, Nikki Haley, proved deeply unpopular with the party’s base and could struggle to win over Trump’s delegates if he were not the nominee.
Has this happened before?
Many Americans will have no memory of the 1968 Democratic primary, when President Lyndon Johnson announced he would not seek re-election after only narrowly winning the party’s New Hampshire primary contest in March. Weeks prior, Senator Robert F Kennedy had launched his campaign for the party’s presidential nomination. He was assassinated in June, after winning the California primary.
Johnson’s vice-president, Hubert Humphrey, eventually accumulated enough delegates through the support of party insiders to win the Democratic nomination. But the convention that year was so disastrous for the party, which went on to lose the presidential election, it prompted an overhaul of the entire primary system, resulting in the contest-driven nominating process in place today.
What if a vacancy arises after the convention but before election day?
Here again the political parties would play a central role.
The Democratic National Committee and the Republican National Committee have slightly different rules guiding how they would replace the deceased presidential nominee by majority vote.
According to party rules, the DNC has the power to fill the vacancy on their party ticket after the chair consults Democratic governors and congressional leaders. The RNC, according to its rules, could reconvene a national convention or select the alternative candidate itself.
For simplicity, the parties would probably consider the running mate, but there is no guarantee.
If there were enough time, the replacement candidate might appear on the ballot. But states have different ballot filing deadlines and several states begin mailing their ballots as early as September.
In states where ballots have already been printed or mailed, the party could instruct voters – and electors – to treat the names at the top of the ticket “as hieroglyphics”, said Derek Muller, a law professor at the University of Notre Dame.
“If it says Biden-Harris, you should interpret that as Harris-Booker,” he said, offering the hypothetical example of an alternative Democratic ticket with the New Jersey senator Cory Booker as Harris’s running mate.
Has this ever happened before?
No. But there are some examples of how this might play out.
In 1972, the Democratic vice-presidential candidate, Senator Thomas Eagleton, was forced to withdraw from the ticket after the convention following reports that had been treated for mental illness. The Democratic National Committee convened a meeting in Washington to select Eagleton’s replacement, Sargent Shriver.
Experts also point to 2000, when the Democratic candidate for a Senate seat in Missouri, the state’s governor, Mel Carnahan, died weeks before the election. The state’s lieutenant governor, a Democrat who ascended to the governorship, committed to appointing Carnahan’s wife, Jean, to the seat if he won posthumously, which he did. She was then appointed to fill her late husband’s seat.
“The electorate can learn about these things if given the cues to do so,” Muller said.
Could Congress delay the election?
It is possible but improbable. The date of the election is set by federal law, the Tuesday after the first Monday in November, which is 5 November.
Both chambers of Congress would have to approve a measure delaying the election, and the president would have to sign it, unlikely in a divided government.
Even if it were to happen, Congress could only push the election by a matter of weeks because the constitution states that a president’s term “shall end at noon on the 20th day of January”.
What happens if the candidate is incapacitated, not dead?
Timing would still matter. The rules and laws would still apply. But the scenario takes on a new degree of complexity.
“All of these questions become much more complicated in situations where you have a disability or you’re physically unable to take the oath,” Muller said. “There are just more contingencies in place that you don’t have when it comes to death.”
What if the winning candidate dies after election day?
It is important to remember how the presidential election process works. To win the White House, a candidate must accumulate a majority of electors – 270 – in the electoral college. In each state, political parties choose slates of electors and voters cast their ballot for a party’s electors.
“When you vote for president, you’re actually not voting for Joe Biden or Donald Trump,” Kamarck said. “You are voting for a slate of electors who have been chosen in that state as part of the electoral college.”
After the election, the winning presidential candidate’s slate of electors, generally party loyalists vetted by local party leaders for the role, meet in their states to cast their votes for president and vice-president. This year, that occurs on 17 December.
Some states “bind” electors to vote for the winner of the election in their state, laws that were upheld by the supreme court in a 2020 ruling, but other states allow electors more independence to cast “faithless votes”. The supreme court justice Elena Kagan added in a footnote that “nothing in this opinion should be taken to permit the states to bind electors to a deceased candidate”.
If the electors haven’t met when the vacancy occurs, they would be strongly incentivized to coalesce around a replacement candidate designated by the party. The running mate would be an obvious choice, but, again, not the required one.
The electors could also decide to back the deceased candidate and under the 20th amendment the vice-president-elect would become the president-elect. More on this later.
What happens if the winning candidate dies before Congress declares a winner?
A newly elected Congress will meet on 6 January to certify the results of the presidential election by counting the electoral votes. Traditionally this has been a ceremonial affair. But in 2020, a violent mob of Trump supporters overran the US Capitol in a failed attempt to prevent Congress from certifying Biden’s victory.
In this polarized and charged environment, there are concerns about how elected officials in Congress would handle a situation in which the winner of the electoral college vote cannot assume the presidency. Reforms made after the 6 January insurrection on the Capitol made it harder for members of Congress to object to the counting of certain electoral votes, a partisan practice.
But Congress would be operating in uncharted territory.
Is there a precedent?
No. No winning presidential candidate has died in the period between election day at the start of November and the inauguration on 20 January.
But there is one example of a losing presidential candidate dying after election day. In 1872, the Democratic presidential candidate Horace Greeley died after losing the election to Ulysses S Grant but before the casting of the electoral college votes. Although his death did not affect the outcome, there was a debate over what to do with the 66 electoral college votes he had won. Most electors chose to cast their votes for another candidate and Congress chose not to count the three votes cast for the deceased Greeley.
Some experts say Congress’s decision not to count the votes should not necessarily be taken as precedent, especially because it occurred before the 20th amendment was ratified. Others argue that members of Congress might have decided the matter differently if the votes would have affected the outcome.
So what does the 20th amendment say?
Section 3 of the 20th amendment states: “If, at the time fixed for the beginning of the term of the President, the President elect shall have died, the Vice-President elect shall become President.”
But there is some debate over when a winning candidate becomes president-elect. Is it after the electors vote on 17 December or not until a joint session of Congress counts the electoral votes on 6 January?
“The balance of scholarly opinion holds that the president- and vice-president-elect are chosen once the electoral votes are cast,” according to a 2020 Congressional Research Service memo. But the law itself leaves some ambiguity.
How will it look to voters?
Amazingly, these are only some of the hypothetical scenarios that could unfold.
If the unexpected occurs, parties will jockey for political advantage and bad actors would probably try to seize on the chaos. This will be especially true in the event the election results are contested, as Trump is laying the groundwork to do, or in the “nightmare scenario” neither candidate earns 270 electoral votes.
With the election expected to be narrowly decided, there is no doubt an unexpected vacancy would jolt a system already rattled by an onslaught of spurious claims and political misinformation.
Holly Idelson, a policy advocate with the non-partisan group Protect Democracy, said education and public awareness will be critical to defuse the potential for a “crisis atmosphere” in the circumstance of a presidential candidate’s death or withdrawal.
“Yes, there are unprecedented scenarios that could arise, and yes, there may be genuine questions about how to apply the law, but in many cases there is law to apply,” she said. “We should focus our efforts on promoting regular order rather than undue alarm.”
• This article was amended on 6 May 2024 to correct the number of electoral college members to 538; a previous version incorrectly said there were only 535 members. Also, text was revised to clarify the provisions of the 25th amendment.
