There was a lovely little story in Analog decades back, where both parties took the curse seriously, aand put a woman and a black man into the top slots as sacrificial lambs. But the kerfuffle took so long that the election was deelayed to the odd year ... meaning they didnt die. Then the ASBs who had arranged the whole curse flew home.To take this to the next step, what happens when Regan takes the bullet in the heart, vs the near miss? Obviously GB Sr will hit the term limit thing in 1988, so some one else will be president when Saddam makes his inquiry about the US attitude vis Kuwait, ect...
There is also the question of if Bush Sr will be competitive in the 1984 election?