The title is pretty self-explanatory. I remember hearing a quote that said (I'm paraphrasing), "Politics is the art of getting people to want to please you." Politicians, as a group, become hugely successful because they're able to win people over through personal charm (e.g., Clinton or Reagan) or rarely, railroad people into doing what they want through sheer force of will (LBJ). Nixon? Well...
Besides his well-known curmudgeonly public persona, Nixon's personal relationships seem to be highlighted by his own stiff/insecure/paranoid/out-of-touch nature (recent example: Google the phrase "Nixon girls don't swear"). Nobody actually seemed to like Nixon, even if many in his inner circle greatly respected him. Yet somehow he managed to elevate himself from obscurity to national profile multiple times.
So how the hell did everybody's weird Uncle keep winning popularity contests?
I'd like to point out that Nixon really could be charismatic when he wanted to. The guy was a champion debater and knew how to sound convincing, and seemed to know what he was talking about.
Now as we all know, he looked like a curmudgeon in the 1960 debate against Kennedy. In Nixon's defense, everyone looks uncharasmatic when opposite Kennedy. But Nixon does look less lively compared to his earlier speeches while on campaign. It could have been that he was not used to speaking directly to camera because television was still fairly new or it could have been that his campaign told him to scale it down a notch to "look more presidential".
Fast forward a bit, LBJ fell from an approval rating of 78 in 63' to as low as 36 in 68'. Now people critisized LBJ for a variety of things, but for the sake of brevity I'm going to go with the easy answer and say the entire county was pissed at him over Vietnam. And Nixon's campaign exploited this beautifully. Because one thing everyone should agree about Nixon, is that he is by no means an idiot. Even in 68, he was definitely older and less energetic, he still had an acceptable amount of charisma and still knew how to compose and deliver a pretty good speech.
Also in 68', Nixon was in an amazing position. He was a former governor of California, the most populous state in the union. The nation was pissed at the present administration over an unpopular war. And though I can't prove this, I am pretty sure there was there was quite a bit of nostalgia for the Eisenhower administration. And with Ike in no way to run, his Vice President, Nixon, was in a great position to carry his baton and ride that nostalgia.
Now where I think Nixon's reputation of being a complete void of charisma is due to his press conferences during Watergate. In his defense, this was an older Nixon under much pressure and I imagine, completely mad at the world. But even his resignation speech was handled fairly well.
Though by the time he was part of the famous Frost/Nixon interview in 77' he sounded at his most "Futurama". Again, in his defense, he was older, and this interview was completely unscripted and he was caught off guard.
But we shouldn't underestimate the effect Futurama had on his memory.
As an aside: there is a big difference between 2008 scripted Obama and 2014 Obama without a script. It seems like the stress of the office could make the most charismatic person look terrible when not given a prepared script.
Part answer, part follow-up question: I think I heard somewhere that during the upswing of his career, Nixon was less charismatic than his competition, but was nonetheless better at using the new emerging medium of television to control how he was perceived. Is there any validity to this assertion?