Best candidate losing party could nominate since 1948

[Cryptic]

1948: Dwight Eisenhower - Republicans would've returned to the White House four years earlier.
1952: Adlai Stevenson - I don't see any other Democrat doing better against Ike in '52.
1956: Lyndon Johnson - would've performed better than Stevenson that year, but still loses to the popular Ike.
1960: Nelson Rockefeller - probably would've narrowly beaten Kennedy, pulling more undecideds and independents than Nixon did historically.
1964: Nelson Rockefeller - would've performed better in the Northeast, but still loses. No Republican was going to beat Johnson in '64.
1968: Robert F. Kennedy - the myth of Camelot would've been a big help for the Democrats and he pulls out a win.
1972: Hubert Humphrey - would've performed better than McGovern, but still likely loses given Nixon's popularity at the time.
1976: Ronald Reagan - he isn't tied to the Nixon administration and he's a much better campaigner than his opponent.
1980: Ted Kennedy - rallies the base and performs better in the Northeast, but still loses due to the economy.
1984: Gary Hart - would've done better, but still loses given Regan's popularity.
1988: Mario Cuomo - performs better and could potentially win, if his campaign can handle the inevitable Atwater mudslinging.
1992: George H.W. Bush - the sitting President was the best they could've realistically run that year. Between the excellent campaigning of Clinton and the strong candidacy of Perot, Republican victory in '92 was unlikely.
1996: Colin Powell - popular general and the prospect of the first black President would've been the GOP's best shot against popular incumbent Clinton.
2000: Al Gore - the sitting Vice President is still the best choice, despite losing historically. It's easy to imagine any number of different decisions handing him victory.
2004: Wesley Clark - a former general with real military experience would've been the best angle to attack Bush.
2008: John McCain - honestly was the best pick for the GOP in '08. I don't see Romney or Huckabee doing any better once the recession started.
2012: John Huntsman - doesn't pander to the Tea Party and pulls more moderates and undecideds as a result.