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One Year From The Iowa Caucus: What We Know

We’re one year out from the official start of the 2016 caucus and primary season. On Jan. 18, 2016, men and women will gather in churches, living rooms and school gymnasiums across Iowa to vote in the Democratic and Republican caucuses. So, where do the potential candidates stack up with 12 months to go? And how much stock should we put in their standing?

First things first, take a look at this chart showing Iowa caucuses since 1972 without an incumbent president or “favorite son” running.


Let’s take the parties one at a time.

The Democrats

On the Democratic side, Hillary Clinton is in the most dominant position ever for a non-incumbent. In a late October Fox News poll of Iowa Democrats, she earned 62 percent of the vote. Elizabeth Warren, who has since said she is not going to run in 2016, came in second with just 14 percent.

Does Clinton’s big lead mean anything?

At first glance, polling conducted about a year before the caucus doesn’t have a great record of predicting wins and losses. The early poll leader has lost the caucus six times; the early leader has won five times.

Yet many of the early leaders who went on to lose, such as Mitt Romney in 2012, were leading the field with just a small plurality of support. The bigger poll leaders, not surprisingly, did better. Walter Mondale in 1984, Gary Hart in 1988 and Al Gore in 2000 come closest to Clinton’s current standing. Both Gore and Mondale won, while Hart dropped out because of the Donna Rice scandal and only re-entered late in the campaign.

More to the point, early polls do a decent job of capturing the eventual percentage the early leader will get. The median error rate for the front-runner is 9 percentage points. The only example of a scandal-free front-runner really falling is Bob Dole in 1996, and he nevertheless won the caucus and the nomination.

Still, we don’t have a lot of data points. Based upon the prior 11 elections, a candidate polling at 62 percent at this point has about an 80 percent chance of winning the Iowa caucus. That’s not too far from the betting markets, which give Clinton about a 75 percent chance of winning the nomination, but 11 elections just isn’t enough for any high degree of confidence.

The Republicans

The Republican race, meanwhile, is a complete mess. The “front-runner” at this point (should he run) is Romney. But pay attention to those scare quotes. A poll this month from Gravis Marketing put Romney atop the field with 21 percent. Jeb Bush claimed 14 percent. As the above table shows, Romney is close to where he was at this point four years ago, and Romney lost the caucus then (though by just one impeccably coiffed hair).

Indeed, Romney is one of the weakest front-runners in history. Someone polling at only 21 percent now has only a 22 percent chance of winning the Iowa caucus (again though, that calculation is based on just a few data points).

It’s rare to win the caucus with less than 30 percent of the vote. Yes, Dole did it 1996, and Rick Santorum did it in 2012, but 12 of 14 caucus winners (“uncommitted” won in 1972 and 1976) when no incumbent was running took at least 30 percent of the vote.

So, who might win the Republican caucus? When there is no clear front-runner in the early polls, it’s anyone’s ball game. Mike Huckabee in 2008 and Santorum in 2012 were polling at either 0 or 1 percent in the early polls. Both relied upon a base of evangelical and born-again Christians, who tend to decide whom to vote for just before the caucus. The small sample size though for those polling as poorly as Romney means that we shouldn’t overplay patterns in the data.

One year out, the Republican side looks a lot more exciting than the Democratic race. Just remember not to make too much of the eventual result among Republicans. Without an incumbent running, the winner of the Iowa caucus has gone on to win the nomination just two out of six times.

Harry Enten was a senior political writer and analyst for FiveThirtyEight.