With the health of Hillary Clinton under scrutiny, has there ever been a candidate who died or became unable to run during the general election? | AskHistorians Archive Observer

With the health of Hillary Clinton under scrutiny, has there ever been a candidate who died or became unable to run during the general election?

by TheSquiggolo

Whether it was due to sickness, assassination, or freak accident, has there ever been a case of a candidate no longer being able to run this far along in the process?

Searocksandtrees

FYI, there was a tangential conversation on this question earlier today here

William Henry Harrison infamously died from complications due to pneumonia some 30 days into his presidency. Was his health or age (at 68) ever a significant issue during his bid for office?