Former vice-president George Bush had been dealt a good hand: a strong economy and stable international relations, virtually ensuring him a presidential victory. Then the Democrats helped out by nominating Mike Dukakis.
Mario Cuomo was favored by many Democratic operatives for his intelligence, but then Mario showed it by refusing to run.
Gary Hart was attractive to many voters, one in particular. Regarding allegations of adultery, he told The New York Times that if they followed him around, they'd "get bored." It was not The Times that followed him, but The Miami Herald who got pictures of Hart with sexy Donna Rice on his lap. This would have been bad enough, but Hart was wearing a shirt that said, "Monkey Business Crew." Thus ended Gary Hart.
Dukakis was left. Dukakis was an old-school New-Deal Democrat from Massachusetts, a self-proclaimed "proud liberal," ie, a sacrificial lamb. At the convention, Dukakis' name was placed in nomination by a rising star in the party named Bill Clinton. Bill's speech went on so long, delegates began booing him to finish.
During the campaign, Bush derided Dukakis for his "Harvard Yard" political views. When it was pointed out Bush himself had gone to Yale, Bush said that was a different thing entirely.
Dukakis' most memorable gaff was a photo op in which he drove a tank outside a General Dynamics plant to prove his support for the military. Dukakis had an impressive resume in many respects, but he looked ridiculous with his head sticking out the hatch in a helmet. This, the voters could never forgive.
George Bush: 426
Michael Dukakis: 111