Let me start by saying that a comparison between Carter and Trump is not a discussion of shared character. Carter is a smart, decent fellow; Trump is a rogue. Both got elected -- barely -- against weak opponents. Sure, Ford was an incumbent, but he had never been elected to any statewide office, which showed in a campaign that got up to speed too late to win. Hillary Clinton got raked over the coals for minor stuff in contrast to what Trump got away with. If Carter had one of the cleanest administrations ever, Trump has (to parody the title of a book about Lincoln) a "team of shysters". Trump has been lucky so far with the economy and on foreign affairs, but it is not clear that Americans will suffer the corruption and cruelty of the Trump Presidency with delight in 2020.
In any event, here's 1976 as shown by margin:
Ford 10% or more (saturation 9 for 20% or more)
Ford 5-9.99%
Ford under 5%
Carter under 5%
Carter 10% or more (saturation 9 for over 20%)
Carter/Mondale 297 (50.08% popular vote Ford/Dole 240 (48.01% pv)Carter won in the South, winning every former Confederate state except Virginia (which in 2016 was the only former Confederate state that Hillary Clinton won!) in part by fitting the cultural norms of the South. His political agenda, basically the anti-corporate attitude of Southern agrarians of the New Deal Era but without the racism, was apparently good for but one election. If he had been a successful President he might have picked up states like California, Illinois, Iowa, New Jersey, and Washington (maybe Michigan if he did not have to face a Favorite Son in Gerald Ford) to offset losses in the South. Note well that he is the last Democratic nominee to have won Alabama, Mississippi, South Carolina, or Texas.
Carter had some good ideas for reforming the federal government (like zero-based budgeting), but Congress rejected them. Nobody has tried to introduce them anew. After that he was an unsuccessful President by every standard except integrity. Here's what happens to a President who barely got elected the first time and lost badly in a re-election bid:
Reagan 10% or more (saturation 9 for 20% or more)
Reagan 5-9.99%
Reagan under 5%
Carter under 5%
Carter 10% or more (saturation 9 for over 20%)
Reagan/ GHW Bush 489 (50.75% pv)
Carter/Mondale 49 (41.01% pv)
It looks as if someone spilled some Prussian blue dye on a map of the United States. Carter was somewhat effective in appealing to Southern sensibilities.
