What happens if a presidential candidate dies?

President Donald Trump is battling Covid-19. Former Vice President Joe Biden will soon turn 78 years old. And early and mail-in voting in the 2020 presidential election has already begun in many states.

So what happens if a major-party presidential nominee doesn’t make it to Inauguration Day?

The most likely outcome this year is that the deceased candidate’s running mate would effectively replace him — Mike Pence for Trump, and Kamala Harris for Biden. But depending on when it happens, it’s not an entirely sure thing, and it could be messy getting there.

The process for installing a new president is complex, involving multiple steps. First, there’s Election Day itself, on November 3. Second, the Electoral College will vote, on December 14. Third, Congress will count the Electoral College votes to formally certify the outcome on January 6. Fourth and finally, the winner is scheduled to be inaugurated on January 20.

The death of a major-party presidential nominee would have different implications depending on precisely where in that period it falls — and, of course, on whether the deceased candidate loses the election (something that has happened once before), whether the deceased candidate wins (something that hasn’t happened before), or whether the election is disputed (buckle up).

First off, what would happen if a major-party nominee dies between now and Election Day (November 3)?

Since it’s already early October, ballots have been finalized in many states, and early and mail voting has already begun. So it’s almost surely too late to change the names on the ballot at this point. The only practical way to make that happen would be to postpone the presidential election, and a bipartisan agreement to do that is very tough to imagine.

But voters can vote for a dead candidate. In 2000, Missouri Gov. Mel Carnahan was the Democratic nominee for that year’s Senate race in the state. He died in a plane crash three weeks before the election, too late to have his name removed from the ballot. But Democrats had announced that Carnahan’s widow would be their choice for the seat, and the state’s new governor had agreed to appoint her to the seat if Carnahan won — which is what happened.

For the presidential race, the DNC and RNC have processes by which they can replace a deceased nominee. Both say, essentially, that they get to pick the replacement by majority vote (the RNC says they could also reconvene their convention to pick a replacement, but that likely wouldn’t happen this year). Either party can still do this to “replace” the nominee after the election and before the Electoral College votes on December 14 — but the problem is that it’s already too late to get a new nominee’s name actually on state ballots.

What either party could do in the event of an untimely death, though, is make clear who the designated successor would be. And for both, there’s an obvious choice: the VP nominee, whose name is actually on the ballot. (Voters aren’t just voting for Trump or Biden; they’re voting for electors who have pledged to support the Trump-Pence ticket or the Biden-Harris ticket.)

That wouldn’t necessarily be the end of the story since the electors have to vote, as we’ll get to next. And it’s important to note that the DNC or RNC doesn’t technically have to pick the VP nominee to replace a deceased presidential nominee — they could theoretically pick somebody else, or split into factions backing different contenders.

But this year, this soon before the election, each party would be highly incentivized to encourage their supporters to just vote for the ticket as planned (rather than, say, to have write-in votes for a new nominee), and to pick the closest thing to a unity choice: Pence for Republicans, Harris for Democrats.

The next stop on the road to Inauguration Day is December 14, when the Electoral College actually votes.

Remember, if a presidential candidate wins a state, what technically happens is that his party’s chosen slate of electors becomes the electors for that state. The 538 electors from the entire country — the Electoral College — then actually choose the president. In modern times, they basically just rubber-stamp the Election Day results.

The death of a major-party nominee would present a very unusual situation. But the ramifications would be quite different depending on whether the deceased candidate won or lost on November 3, or whether the outcome was disputed.

If the losing candidate dies, then, well, the winner still wins. This happened once before in US history, in the election of 1872. President Ulysses S. Grant won reelection, and his main opponent, Horace Greeley, died a few weeks later, before the Electoral College voted.

Greeley won six states and 66 electoral votes, so after his death, those electors then had to decide what to do. Their votes ended up split among five people (one of whom was Greeley himself, though those votes weren’t counted by Congress). But it didn’t really matter what Greeley’s electors did because there weren’t very many of them — Grant had clearly won.

So what if the winning candidate dies? Here, there could be an attempt from the RNC or DNC to designate a replacement — again, the vice president-elect would be the obvious but not required pick — and to have all the electors pledged to, say, Trump, vote for Pence for president instead.

The electors won by a candidate are generally loyalists for that candidate’s party vetted by state party leaders, so it’s entirely possible they’ll move their votes in lockstep to the deceased candidate’s replacement. But there are potential problems.

First, electors aren’t always so perfectly loyal — some “faithless electors” break their pledges and vote for someone else, and there was a record seven such electors in 2016.

Second, in an attempt to prevent this faithless behavior, states have adopted laws requiring electors to vote for the candidate that won their state. The specifics of these laws differ by state, and some are toothless. But if taken literally, they could bind electors to vote for the deceased candidate — locking them in.

In the unusual situation of a candidate’s death, most electors for the deceased candidate would probably defy those pledges, if asked to do so by the party. Indeed, a Supreme Court decision upholding the constitutionality of these penalties on faithless electors mentioned just this possibility. “We do not dismiss how much turmoil such an event could cause,” Justice Elena Kagan wrote in her majority opinion.

Kagan wrote that the Court suspected that states would “release electors from their pledge” in this situation. And she clarified that “nothing in this opinion should be taken to permit the States to bind electors to a deceased candidate.” Still, in a close contest, there could be the opportunity for some partisan shenanigans and legal wrangling over this.

So there may be another option: that the electors just vote for the deceased winning candidate, as planned.

The 20th Amendment to the Constitution 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.” So perhaps a majority of the Electoral College could simply stick with what the ballots said and make the deceased presidential nominee president-elect and the VP nominee vice president-elect.

Whether that flies will depend on the next stage in the process: Congress.

On January 6, 2021, a joint session of the newly elected Congress will gather to make official the results of the presidential election by counting the Electoral College votes.

In recent decades, this has mainly been a formality. But Congress does have the power to consider and rule on objections to the counting of certain electoral votes. If there is an objection from any member of Congress, the House and Senate will each decide what to do with the objection. And if a majority in both the House and Senate vote to sustain the objection, then the electoral vote or votes in question won’t be counted. (If just one chamber votes to sustain the objection, that means the objection fails.)

So what if a majority of the Electoral College voted for a dead presidential candidate — either knowingly for a candidate who died beforehand or for a candidate who died after they voted — and there’s an objection in Congress?

As mentioned above, the only precedent we have is ominous. When three electors tried to vote for the late Horace Greeley in early 1873, Congress disqualified their votes, on the understandable grounds that Greeley was dead.

But that was before the 20th Amendment existed. Ratified in 1933, this amendment makes clear that the vice president-elect becomes president if the president-elect has died by Inauguration Day.

Except there’s one thing that’s a bit unclear about it: When, exactly, does the winning candidate become “president-elect”? Is it after the voters themselves vote on Election Day? Is it after the Electoral College votes are cast in mid-December? Or is it after Congress counts the Electoral College votes in early January?

According to Thomas Neale of the Congressional Research Service, the amendment likely kicks in once the Electoral College votes are cast. Neale cites a House committee report from the time the amendment was approved, which defines “president elect” as “the person who has received the majority of electoral votes,” and states that “the person becomes the President elect as soon as the [electoral] votes are cast.”

Here, again, as at all stages in the process, the solution to a dead president-elect seems obvious — turn to the vice president-elect — but this has never been tested in practice. And again, there is the potential for mischief in a close contest, especially if both chambers of the new Congress are controlled by a different party than the deceased winning candidate.

Saving the most chaotic possibility for last, it is also possible that the presidential election’s outcome will be very close or disputed.

And if a candidate dies in that scenario — well, all bets are off.

President Trump has clearly been laying the groundwork to try to contest the results of a close election, with baseless claims of fraud in mail voting and declining to promise a peaceful transfer of power. Some leading Democrats are also saying they want any close results to be vigorously contested — Hillary Clinton said Biden “should not concede under any circumstances,” and John Podesta took Biden’s role in a “war game” simulating the 2020 election and refused to concede after a Trump Electoral College win.

Barton Gellman of the Atlantic has also reported on potential shenanigans from Republican-controlled legislatures in swing states, which could involve disregarding the vote totals in their state to appoint partisan electors, based on claims of fraud. Some of those states have Democratic governors, who could then refuse to certify the vote totals. Congress might have to step in, and the courts could get involved as well.

For now, this is a parade of hypothetical horrors, and without knowing further specifics of the dispute, it’s impossible to game out exactly how it would unfold. But if the race tightens and the outcome is contested — and then a candidate death is thrown into the mix — things could get explosive. Expect even extremely dubious legal theories to be floated as both parties try to seize any advantage they can get.