Beto O'Rourke dropped out, here's who stands to gain.

• Former Rep. Beto O'Rourke dropped out of the 2020 race.
• About 20% of Democrats would have been satisfied with him as the nominee, even if he wasn't their first choice.
• With O'Rourke out of the race, three quarters of people who like him also like Sen. Elizabeth Warren, and two thirds like Sen. Bernie Sanders and former Vice President Joe Biden.
• Sens. Kamala Harris and Cory Booker perform disproportionately well among his supporters.

Former Rep. Beto O'Rourke's exit from the 2020 campaign comes at a transitional time in the race, when a number of candidates who have been promising but unable to capitalize are about to get caught between the hammer and anvil of fundraising and bills.

This is a really interesting time for the race, because with a few exceptions - Sen. Kirstin Gillibrand chief among them - most of the exits is the 2020 Democratic presidential primary have come from candidates who had low name recognition or support.

But with O'Rourke's exit, you're looking at a candidate who was seen as a viable nominee by a fifth of the Democratic electorate, even if he wasn't their first choice for the job. This means that one in five Democrats will be down a contender, and it is an opportunity for rivals still in the game to capitalize and make a play.

Insider has been conducting a recurring series of polls since last December, asking people who identify as Democratic primary voters who among the Democratic candidates for the president they're aware of, who they'd be satisfied with as nominee, and who they wouldn't be.

This allows us to figure out who's assembling a viable coalition and who's competing with one another over that coalition. Other pollsters who pursue topline data - asking which one candidate the respondent supports - miss out on that, and it's times like these when a candidate drops out that we get a great look at who's in contention to reap the support of the Beto O'Rourke fans.

Why Beto O'Rourke dropped out

This part is fairly simple.

This is the percentage of people aware of Beto O'Rourke who would have been satisfied in the event that O'Rourke was the nominee:

Not to veer into statistical jargon here, but that this chart going down is widely interpreted by political scientists as "not great."

Given that over the course of five months O'Rourke was unable to get the chart to go back up again, he does not get to be the president. Like I said, fairly simple.

How many people actually supported Beto O'Rourke?

This is a really great question, and there are two different answers. The most common refrain you'll hear is that not a lot of people supported O'Rourke and that he was in serious jeopardy of missing out on the second debate.

According to the latest data from Morning Consult, just 2% of respondents to its poll of 15,431 people conducted between Oct. 21-27, 2019 listed O'Rourke as their top choice, a figure that fell to 1% when concentrating only on respondents who live in the four early primary states of Iowa, New Hampshire, South Carolina, and Nevada.

That's all true! But there are way more people who liked O'Rourke than people who liked O'Rourke the most.

Based on the seven polls Insider conducted since the last week of August, about 20% of Democratic primary voters we surveyed would have been satisfied with Beto O'Rourke as nominee. About 62% of Democrats had heard of him, and a third of the people who had heard of him would have been fine with him as nominee. Those numbers aren't terrible: They represent a candidate who came off as generally amenable but never really broke out.

Who will Beto O'Rourke supporters end up backing?

Though he had a lot of fans, it's tough to consider them particularly ardent. Besides the 3 percent of his supporters who liked him and him alone, just 20 percent had it down to O'Rourke and just one or two other contenders. Generally speaking the bulk of people who liked Beto were satisfied with him and 3 to 6 other contenders: 48% of his fans are in that group.

Over the past seven polls, Insider interviewed 624 people who were satisfied with Beto O'Rourke as nominee. Here's the percentage of those people who are satisfied with his ex-rivals:

• Sen. Elizabeth Warren: 76%, 11 points higher than her overall performance among Democrats
• Former Vice President Joe Biden: 67%, 12 points higher than his overall
• Sen. Bernie Sanders: 66%, 10 points higher than his overall
• Sen. Kamala Harris: 58%, 14 points higher than his overall
• South Bend Mayor Pete Buttigieg: 55%, 6 points higher than his overall
• Sen. Cory Booker: 50%, 13 points higher than his overall
• Former HUD Secretary Julian Castro: 32%, 6 points higher than his overall
• Andrew Yang: 31%, 2 points lower than his overall
• Sen. Amy Klobuchar: 27%, 1 points lower than her overall
• Rep. Tulsi Gabbard: 15%, 5 points lower than her overall
• Tom Steyer: 12%, -5 points lower than his overall

Gov. Steve Bullock, Sen. Michael Bennet, Marianne Williamson, and Rep. John Delaney all were liked by fewer than 10 percent of O'Rourke fans.

Who has the most to gain?

Warren is favorable to three quarters of O'Rourke fans and Biden and Sanders are amenable to two thirds of O'Rourke fans. Some candidates do really well among Beto fans compared to their baseline score among Democrats: Sen. Kamala Harris and Sen. Cory Booker all do really well among his supporters.

Indeed, the number of other candidates supported by a Booker fan fell from an average of 5.7 with O'Rourke in the race to just 5.2 with O'Rourke out of it, the largest drop of anyone in the race still.

If there's anything to come of O'Rourke's exit, it's likely consolidation towards the top tier. O'Rourke was appealing for a lot of people, and his exit will help them hammer down their constituencies.

At the least, O'Rourke will have a large roll to play come Super Tuesday: Texas is awash with delegates, and the former El Paso congressman will be a coveted endorsement come March. Because even if he's not someone's first choice, a fifth of the field at least will hear him out.

• Read More:
• This week's presidential debate is do-or-die for Beto O'Rourke
• Beto O'Rourke is running for president in 2020. Here's everything we know about the candidate and how he stacks up against the competition.
• Beto O'Rourke's shaky polling looks like it's not going to get any better, and it's a bad sign for his 2020 prospects
• Why Beto O'Rourke could lose in his quest to win the 2020 Democratic nomination