I'm feeling emotionally unstable right now. I can't stand Trump. He's a horrible person, a nightmare of a leader, and a man who's undeniably guilty of committing crimes while in office. I don't want him to win re-election, period.
That being said, I don't want the guy dead. I don't! You can dislike a person for their politics, and hope they live a long life. I can say the same thing about the litany of Minnesota Republican officials who were exposed to COVID-19 by Trump and his campaign staff. I dislike your wealth worshipping at the expense of 95% of this country, but here's to your health! I'm consistent. I've wanted people to be healthy and safe from Corona Virus; ALL people.
With Trump's worsening condition, there has been a question of what would happen if a candidate for the Presidency died a few weeks before the election. The answer is unless both the House of Representatives and the US Senate vote to delay the election (something very unlikely), the election will go on as scheduled. The Constitution is pretty clear that only the Congress can delay a Presidential election. The party who lost the candidate could name a replacement, but there's a nightmare of how exactly you vote for that person, especially when early voting has already begun. You can't assume just because someone votes for one political candidate from a party, the same vote would go for a replacement candidate. So if it becomes a write in campaign, the odds they'd be able to pull that off are astronomical.
It boils down to this. There will be an election on November 3rd in the United States, and at the end of the day, either Joe Biden or Donald Trump will win. No one else has a chance.
The other time in American History we had a Constitutional Crisis like this was with the 9th President, William Henry Harrison, better know as the guy who died a month after talking office. A lot of the rules were unwritten then, so we ended up having to create standards about line of succession.
For all your William Henry Harrison knowledge, let's start with the election of 1840 itself, courtesy of Hip Hughes.
From The History Channel's exceptional series on The Presidents, Harrison was the shortest entry, 3 and a half minutes: