Yes, I'll acknowledge that the fact that the three leading contenders for the Democratic nomination all being 70 by Election Day 2020 (as is the Republican incumbent) was what inspired this post--but it is not what I want to discuss. I want to discuss past elections (before or after 1900) when both major party nominees might be over 70.
1996: Bob Dole (R) vs. Lloyd Bentsen (D). (Bentsen has been a successful vice-president under the Dukakis administration of 1988-96. He wins the Democratic presidential nomination in 1996, due largely to a split in the liberal vote among his primary challengers. Alternatively, Dukakis may for some reason die in office.)
1996: Bob Dole (R) vs. Harris Wofford (D) (who was chosen as Bill Clinton's running mate in 1992 and became president when Clinton died in a helicopter crash).
1984: Ronald Reagan (R) vs Edmund Muskie (D). Mondale in this ATL has decided not to run for president in 1984 (instead he had successfully run for the Senate against Durenberger in 1982, pledging to serve out his term). So Muskie becomes the candidate of the moderately liberal Democratic Establishment types who backed Mondale in OTL.
1856: John McLean is the first Republican presidential candidate (he was a serious contender against Fremont for the nomination in OTL). Democrats after a deadlocked convention turn to William Marcy. (That leaves the Know Nothings--but some conservative Republicans hoped that Fillmore would withdraw in favor of McLean if the Republicans nominated the latter.)
1852: Democrats nominate Lewis Cass (this is perhaps most likely if they had lost with a candidate other than Cass in 1848--but even in OTL Cass led on the first nineteen ballots https://en.wikipedia.org/wiki/1852_Democratic_National_Convention). Whigs nominate Daniel Webster (Fillmore makes it clear he will not run, so southern and conservative northern Whigs rally behind Webster as the only man who can beat the Seward-backed Scott). The bitterness Webster felt about being turned down for the nomination may have hastened his death in OTL so maybe he lives at least until Election Day in this ATL.
Any other ideas? (I can see the Republicans nominating Levi Morton in 1896 but it's hard to think of a plausible Democratic nominee that year who was 70 or older).
1996: Bob Dole (R) vs. Lloyd Bentsen (D). (Bentsen has been a successful vice-president under the Dukakis administration of 1988-96. He wins the Democratic presidential nomination in 1996, due largely to a split in the liberal vote among his primary challengers. Alternatively, Dukakis may for some reason die in office.)
1996: Bob Dole (R) vs. Harris Wofford (D) (who was chosen as Bill Clinton's running mate in 1992 and became president when Clinton died in a helicopter crash).
1984: Ronald Reagan (R) vs Edmund Muskie (D). Mondale in this ATL has decided not to run for president in 1984 (instead he had successfully run for the Senate against Durenberger in 1982, pledging to serve out his term). So Muskie becomes the candidate of the moderately liberal Democratic Establishment types who backed Mondale in OTL.
1856: John McLean is the first Republican presidential candidate (he was a serious contender against Fremont for the nomination in OTL). Democrats after a deadlocked convention turn to William Marcy. (That leaves the Know Nothings--but some conservative Republicans hoped that Fillmore would withdraw in favor of McLean if the Republicans nominated the latter.)
1852: Democrats nominate Lewis Cass (this is perhaps most likely if they had lost with a candidate other than Cass in 1848--but even in OTL Cass led on the first nineteen ballots https://en.wikipedia.org/wiki/1852_Democratic_National_Convention). Whigs nominate Daniel Webster (Fillmore makes it clear he will not run, so southern and conservative northern Whigs rally behind Webster as the only man who can beat the Seward-backed Scott). The bitterness Webster felt about being turned down for the nomination may have hastened his death in OTL so maybe he lives at least until Election Day in this ATL.
Any other ideas? (I can see the Republicans nominating Levi Morton in 1896 but it's hard to think of a plausible Democratic nominee that year who was 70 or older).