And while you might think anecdotally that presidential primary history is rife with frontrunners laid low by the time the delegates are awarded, the reality is very much the opposite. In 2016, for example, presumptive frontrunner Jeb Bush never polled more than 17 percent, as Donald Trump led the polls nearly every day from July 2015 onward. At this point in 2012, Mitt Romney led a crowded field of GOP hopefuls, and despite briefly falling behind Herman Cain and then Newt Gingrich, went on to win the nomination comfortably. While early polling has tended to be more predictive for Republicans than Democrats, it isn’t meaningless either.
Early frontrunners have certainly coughed up leads. There was, of course, the 2008 Democratic primary, in which Hillary Clinton led eventual nominee Barack Obama by an average of 15 points from July to June 2007. Clinton, however, still nearly won the nomination and fought Obama to a tie in the popular vote totals. The last time someone who wasn’t polling in the top tier at this point in the cycle won the Democratic nomination was 1992, when Arkansas Gov. Bill Clinton climbed past California Gov. Jerry Brown and a number of other more well-known candidates to win, a race that should remind us of how a lack of name recognition can hamper early numbers for candidates who later catch fire. But overall, 1992 might as well be Greek antiquity in terms of American political dynamics.