For the Democrats, Iowa and New Hampshire are not always accurate and they don’t even usually pick the same winner. [It’s also been known to happen that the winner of neither goes on to win the nomination, just ask Bill Clinton.] Then South Carolina has gotten it right…about 66% of the time. Not exaclty a sure thing either. Although it’s unlikely that someone could win their nomination without winning any of the first three states, that doesn’t really help us in a two-person race like the one between Bernie and Hillary.
Now over on the Republican side, things are a lot clearer. In New Hampshire, the winner of the state primary has won the eventual nomination 13 out of the last 16 times, or roughly as far back as the wikipedia chart goes. So since the beginning it has been astoundingly predictive. And out of the three times the winner of the state primary wasn’t the nominee, the runner-up was.
That means that in the entire history of the state primary no candidate has ever done worse than runner-up and won the nomination. That’s not even close to true for Iowa, which saw John McCain come in fourth there in 2008.
Over on the South Carolina side, the results since 1980 (all that’s on wikipedia’s list) shows that all of South Carolina’s winners eventually went on to win the nomination except 2012 when Newt Gingrich pulled a rabbit out of his hat to beat Romney there. [On the Democrat side for the same time period, Jesse Jackson and John Edwards won, so that’s two misses, but S.C. is also a much better predictor than either New Hampshire or Iowa.] So that’s another state where no GOP candidate has ever done worse than runner-up and won the nomination.
If Trump wins both states, as he appears poised to do, then that makes him a much more formidable contender than most thought. And since the states will likely have two different runners-up, it would make it historically unlikely that either of them would be the eventual nominee. Of course, a race where a guy with no government experience wins the nomination has never happened before, so maybe history isn’t playing too big a role in things, but it does make you finally stop laughing at Trump’s chances.