Is the 2016 election more similar to 1948 or 1976?

[Vosem]

The 1976 primaries are a weirdly close fit to the 2016 primaries (like...scary), but the general elections were totally different. The correct parallel to the 1976 general election would've been Trump starting out with a double-digit lead in June, losing it by late October, and then being bailed out by a Hillary gaffe in the last debate that allows Trump to eke it out after all. Instead, what we saw was a constant bouncing of the lead between a small, single-digit Hillary lead whenever the focus was on her scandals (in hindsight, we realize that the Electoral College distortions mean Trump was winning during these periods) and large, nearly-double-digit Hillary leads whenever the focus was on Trump, and the election concluded during a focus-on-Hillary moment. In this sense there is a comparison to 1980, in which large portions of the electorate had misgivings about Reagan and Carter, though in that case it was Reagan with the constant poll lead, Carter with the large hidden Electoral College advantage, and the race finished on a high Reagan note.

[Vosem]

I picked 1948.  Neither is a great fit, but Hillary was a Democratic Dewey in many ways and Trump was Trumanesque in some ways. 

Carter was nowhere near the outsider Trump was.  He was a Southern Democrat who was looked at by the Democratic Establishment as the person who could best neutralize Wallace in the South (which he did).  They did not count on him winning in IA and NH, however.  The Democratic Party yielded to the inevitability of Carter after a while because it dawned on them that he might actually end the Democrats' slide in the South (which he did, for one election).  He was also a Southern Democrat that, for all his recalcitrance, was on record of saying he'd vote for McGovern, and who showed some interest in bringing Georgia back into the National Democratic Party.

Carter literally spearheaded the national anti-McGovern Democratic organization in 1972. His nomination was a shock in the same way that the next open Republican race going to Ben Sasse would be a shock.