First, although the 1968 election was something of a perfect setup for Republicans — the Democratic Party was divided, the country was in chaos, the incumbent was unpopular — Nixon nearly managed to blow it. His mushy political convictions contributed mightily to this: He didn’t tack far enough rightward to head off George Wallace’s third-party candidacy.
At the same time, he decided to sit on his lead rather than come up with a strong response to Humphrey’s leftward tack toward the end of the campaign. This allowed the race to tighten considerably. Nixon won the popular vote by less than a point, and came awfully close in Ohio and New Jersey to seeing the race thrown to the House of Representatives (which was controlled by Democrats).
The latter parallel should be particularly alarming for Republicans, as Romney seems to have taken a similarly passive approach to the series of “not Romneys.” By failing to make peace with the conservative wing of the party, and by forgoing the opportunity to make an affirmative case for himself, he has placed himself in a precarious position where his nomination is dependent on the other candidates imploding. A similar approach to the general election could blow a historic opportunity for Republicans. After all, Nixon did manage to squeeze through, but he was denied the resounding majority he could have used as political capital to govern. Of course the worst case scenario for Republicans is that Romney mimics the passive Dewey campaign and loses.
More importantly, Nixon’s political malleability did not suddenly end once he was elected.