Hypothetically… What would happen if Trump withdrew from the presidential race? Would the RNC nominate someone else? Is there a timeframe when the names on the ballot become fixed?
The rules of the Republican Party (rule 9) allow the Republican National Committee to name a replacement.
What happens to the ballot is up to each state. For example, Texas allows the state Republican Party to name a replacement up to 71 days before the election. If they miss this 71 day deadline, Trump’s name would remain on the ballot but votes for Trump would count as votes for the Republican electors. Texas Election Code § 192.062. Presidential or Vice-Presidential Party Nominee.
Most states have similar laws (the dates may vary).
The electoral college is the wild card in this–I believe that some states legally bind the electors to vote for the candidate on the ballot, others don’t.
It’s a lot easier to sell the Electors on someone who was actually nominated for office at a party convention than some rando off the RNC’s contingency list.
Not exactly the same thing, but IIRC in 1972 there was a switch of VP after it was publicized that Senator Eagleton had been treated for depression with electroshock therapy:
Note that was Aug 1, so with 3 months to go before the vote - plenty of time to change the ballots - assuming they list vice-presidents too.
Presumably McGovern got to pick, and then the Democratic party pulled whatever levers they needed to ensure the change happened.