Since you may have never seen a Hubert Humphrey advertisement. For a little background, most of Humphrey’s advertising was negative, since he was in the uncomfortable position of being the sitting vice president in a terribly unpopular administration (and had been nominated above other Democrats who were far more popular, despite winning zero primaries). So, the general aim of the campaign was the paint Nixon as out of the loop and untrustworthy.
Here, we see a tactic that pre-dated Karl Rove by decades. Nixon’s biggest strength, at least in his last run in 1960, was his experience. But, eight years out of office, and Humphrey’s campaign could paint this as a weakness: If he was so experienced, what has he ever done? However, Humphrey’s weakness, being part of the Johnson administration, which oversaw the escalation of the unpopular war in Vietnam, was too much to overcome, and Nixon won handily, enough so that George Wallace (American Independent Party) winning the South had no effect.