Former Vice President Joe Biden came in fourth place in the Iowa caucuses with about 13% of the vote, according to preliminary results released Tuesday evening.

Biden came in behind Sen. Bernie Sanders, former South Bend, Indiana, Mayor Pete Buttigieg, and Sen. Elizabeth Warren. As of 5:15 p.m. on Tuesday, Sanders and Buttigieg led with 62% of precincts reporting.

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Former Vice President Joe Biden came in fourth place in the Iowa caucuses with about 13% of the vote, according to preliminary results released Tuesday evening, underperforming his recent polling.

Biden came in behind Sen. Bernie Sanders, former South Bend, Indiana, Mayor Pete Buttigieg, and Sen. Elizabeth Warren. As of 5:15 p.m. on Tuesday, Sanders and Buttigieg led with 62% of precincts reporting.

The results came after an approximately 20-hour delay as a result of a malfunctioning mobile app.

Recent polling of the state showed the leading four candidates bunched closely together in the double-digit range. Biden led or was among the top candidates in recent polls.

There are a host of reasons that Biden may have struggled in Iowa.

For one, his support is concentrated among older voters, who are less likely to participate in a caucus than they are to vote. Iowa caucusgoers are disproportionately younger than the average Democratic primary voter. Candidates like former President Barack Obama, whose base was disproportionately young and progressive, traditionally do better in the Iowa contest.

Crucially, Biden is leading among black Democratic primary voters — something that wasn't reflected in Iowa, one of the whitest states in the country.

But Biden's results in Iowa are surprising in part because of how central the notion of "electability" has become in the Democratic primary. A broad swath of primary voters say they'll support the candidate they believe has the best shot at beating the president in November.

A Gallup poll released on Tuesday showed 56% of Democratic and Democratic-leaning respondents preferred a candidate who has the best chance of beating Trump, while just 42% preferred a candidate who agrees with them on the issues.

While Biden has pitched himself as an electable candidate in the general election, rather than in the primary, such a disappointing showing in Iowa has the potential to undermine his case and slow some of his momentum going forward.

According to Insider's recurring poll, Democratic respondents believe Biden is the strongest general election candidate. For most candidates, a majority of respondents have been unsure of how each person would fare in the general election. But among those who identified themselves as likely Democratic primary voters, about two-thirds have typically said they think Biden would win, which is about double the overall average for the Democrats in the poll.

But because Iowa accounts for only 1% of the country's delegates, it's entirely possible for a candidate to not come in first or win many delegates in Iowa at all and go on to win the nomination, just as Trump did in 2016 after Sen. Ted Cruz won Iowa in 2016.

Grace Panetta and Walt Hickey contributed to this report.