The DNC can nominate whoever they want, but it will be a disaster in Nov.

Many states will oppose this move and protest in various ways. Replacement may not get on all the ballots. It could be significant.

Ballot presence aside, the change of candidate will cost votes, there is no way that a replacement candidate will get more votes than a viable original candidate.

Of course, a replacement might get more votes than a corpse, but the results will likely be lower enough results than a "normal" candidate would typically get that it is pointless to do.

They may just drag Joe across the line and go with plan "B" which is sabotage, traps, barriers and obstruction.

The DNC can nominate whoever they want, but it will be a disaster in Nov.

Many states will oppose this move and protest in various ways. Replacement may not get on all the ballots. It could be significant.

The change of candidate will cost votes, there is no way that a replacement candidate will get more votes than a viable original candidate.

Of course, a replacement might get more votes than a corpse, but the results will likely be lower enough results than a "normal" candidate would typically get that it is pointless to do.

They may just drag Joe across the line and go with plan "B" which is sabotage, traps, barriers and obstruction.