Why do early states matter more in presidential primaries?

Question

There’s a whole ton of attention and polls of places like Iowa and New Hampshire that vote earlier than others in the primaries. Reading sites like FiveThirtyEight, it seems like these are a pretty good predictor of who wins the nomination, and candidates spend tons of time in Iowa. How does voting earlier make a state more important than others for the nomination?

Answer 1

Since 1980, not counting incumbent presidents standing for re-election:

• The winner of the Democratic Caucuses in Iowa won the party's nomination 6 of 8 times.
• The winner of the Republican Caucuses in Iowa won the party's nomination 2 of 7 times.
• The winner of the Democratic Primary in New Hampshire won the party's nomination 4 out of 8 times.
• The winner of the Republican Primary in New Hampshire won the party's nomination 5 out of 7 times.

So they're not necessarily good indicators of who will win, but they are (usually) good indicators of viability.

• With the exception of Bill Clinton in 1992, nobody has won the Democratic nomination without getting at least 22% in the Iowa Caucuses.
• Nobody has won the Democratic nomination without getting at least 24% in the New Hampshire Primary.

(In both cases, counting since 1980.)

Because of this, candidates who do poorly in Iowa and New Hampshire will be seen as nonviable, resulting in a drying up of donations to their campaign and its subsequent end.

Answer 2

How does voting earlier make a state more important than others for the nomination?

It doesn't. If anything, these states are less important. If you check, you will find that the state that goes last is more likely to vote for the eventual nominee than the state that goes first. Why? Because by that time, they've eliminated all the nominees who weren't serious contenders and they've really drilled down into the differences between the candidates. And of course, everyone likes to vote for a winner.

Candidates that can't compete in the early states will have trouble convincing donors that they can compete anywhere. So losing in the early states becomes a self-fulfilling prophecy. Candidates need to be competitive to compete.

Why do they poll the early states so much? Because those are the states where the polls are most meaningful. In the early states, voters are already thinking about the candidates. In later states, they aren't bothering. After all, many of the candidates will have dropped out before their primaries. So polling New Jersey or Oregon can wait. Their voters haven't really started exploring the candidates yet. But voters in Iowa and New Hampshire know that they are going to be picking before the field finishes settling. They are already making up their minds.

The 2020 field is settling down to just three or four truly competitive candidates: Joe Biden; Bernie Sanders; Elizabeth Warren; and possibly Kamala Harris. Yes, Pete Buttigieg, Beto O'Rourke, Cory Booker, Andrew Yang, and Tulsi Gabbard also look like they will make the third round of debates, but they are much less competitive. Unless something happens, they seem set as also rans. The first four states will help cement that. Either a candidate is successful in one of those states, or everyone will assume that the candidate is unable to win states.

It's not that the states are more important for the nomination. It's that they are more important to the reporting at this point. California will determine more delegates than the first four states put together. But we hardly know what the race will look like in California. Will Harris be a top tier candidate? Can she win her home state? Currently polling suggests that she won't. But good performances in the early states might change that. Two of the oldest candidates ever are running. Can they evade tragic health problems? Will the also rans be able to last that long? Or will their supporters be looking for a new choice by California? Those unknowns make it much harder to report on California.

Iowa and New Hampshire often pick different candidates. So a loss in Iowa won't lead most candidates to drop out, as there would still be hope in New Hampshire. But a candidate who isn't at least competitive in one of those states will be really feeling the pressure. And while it's possible to win Nevada or South Carolina after losing the previous states, it doesn't happen that often. The first two states often set the pattern for later states.

Later states are likely to be especially important this time. There are so many candidates that it is quite likely that no one candidate will garner a majority of the vote. So candidates will likely still be fighting to have the most votes even at the end. Meanwhile, a third or more of the votes cast in the early contests won't matter, as their candidates will have already dropped out of the race. Late states like Oregon and New Jersey are unlikely to be deciding, but they will probably be important. Unless of course someone runs away with it by then.