On Monday, Iowa voters did something that Republican “party elites” had failed to do for more than seven months: They rejected Donald Trump.

Trump received 24 percent of the vote in the Iowa caucuses, placing him closer to the third-place candidate, Marco Rubio (23 percent), than to the winner, Ted Cruz (28 percent). Trump underperformed his polls, which had him winning Iowa with 29 percent of the vote, while Cruz and Rubio outperformed theirs.

It’s not uncommon for the polls to be off in Iowa and other early-voting states, but the manner in which Trump underachieved is revealing. It turns out that few late-deciding voters went for him. According to entrance polls in Iowa, Trump won 39 percent of the vote among Iowans who decided on their candidate more than a month ago. But he took just 13 percent of voters who had decided in the last few days, with Rubio instead winning the plurality of those voters.

WHEN DECISION TO SUPPORT WAS MADE TRUMP CRUZ RUBIO Just today 15% 22% 28% In the last few days 13 27 31 Sometime last week 13 36 27 In the last month 23 32 27 Before that 39 26 13 Source: Iowa Republican Entrance Poll

Could this have been a reaction to Trump’s failure to show up for last week’s GOP debate? It’s plausible. Trump, who seemed uncharacteristically chastened in his brief concession speech on Monday, might think twice before skipping a debate again. But there was no decline in his polls in New Hampshire or nationally after the missed debate, which suggests that something else might have been at work in Iowa.

Could it have been his lack of a ground game in Iowa? That’s possible, too. If so, it has interesting implications for the rest of Trump’s campaign. On the one hand, it’s hard to build a field operation on short notice, so if Trump had a poor one in Iowa he may face similar challenges in the remaining 49 states. On the other hand, a field operation potentially matters less in primary states than in caucus states like Iowa.

But there’s good reason to think that the ground game wasn’t the only reason for Trump’s defeat. Republican turnout in Iowa was extremely high by historical standards and beat most projections. Furthermore, Trump won the plurality of first-time caucus-goers.

There may have been a more basic reason for Trump’s loss: The dude just ain’t all that popular. Even among Republicans.

The final Des Moines Register poll before Monday’s vote showed Trump with a favorability rating of only 50 percent favorable against an unfavorable rating of 47 percent among Republican voters. (By contrast, Cruz had a favorable rating of 65 percent, and Rubio was at 70 percent.) It’s almost unprecedented for a candidate to win a caucus or a primary when he has break-even favorables within his own party.

Still, Trump had seemed poised to do it, in part because of the intensity of his support. He’s highly differentiated from the rest of the field — a strategic advantage in such a crowded race — and the voters who like Trump like him an awful lot. The disproportionate media coverage of Trump played a large role too, though. Most Republican voters like several candidates. How does a Republican voter who likes (for example) Trump, Cruz and Chris Christie choose among them? The answer seems to have a lot to do with which candidate is getting the most news coverage.

In Iowa, however, the media environment wasn’t as lopsided in Trump’s favor. Voters were blanketed with ads from all the candidates. And they sought out information on their own before settling on their vote. There was a late spike in Google searches for Cruz and Rubio in the state Monday, bringing them almost even with Trump, even as Trump continued to dominate in search traffic nationally.

What about those national polls showing Trump with support in the mid- to high 30s? They might also be a mirage, reflecting a combination of the Trump base (24 percent is nothing to sneeze at, but also well short of a winning coalition), plus a few other bandwagon-jumpers who come along for the ride but who may peel off as they research the candidates more deeply.

I wrote in August about “Donald Trump’s Six Stages Of Doom” and noted that this might be a problem for Trump. Several past factional candidates, including Pat Buchanan, Pat Robertson and Ron Paul, received somewhere around 25 percent of the vote in Iowa. Under some circumstances, 25 percent can be good enough to win an early state. But it leaves you well short of the majority you need to win a nomination.

What might Pat Buchanan plus obsessive, round-the-clock media coverage look like? Well, possibly a lot like Donald Trump. Iowa voters made Trump appear to be much more of a factional candidate along the lines of Buchanan, who received 23 percent of Iowa’s vote in 1996, than the juggernaut he’s been billed as. We’ll know a lot more after New Hampshire weighs in next week.

Hey, you should sign up for our weekly 2016 newsletter, “What I Thought About Over The Weekend.”

Listen to the latest episode of the FiveThirtyEight politics podcast.