Democratic presidential candidate and former Texas congressman Beto O'Rourke speaks at the University of Nevada at Las Vegas during a campaign stop. (John Locher/AP)

Now that he’s running for president, Beto O’Rourke is not having the reception he had hoped for. We say that not to predict what will happen but to point out that the Democratic superstar of the 2018 midterm elections is not resonating with the party’s base the same way in 2020. At least not right now.

The Washington Post’s Jenna Johnson reports that the candidate who was so buzzy in 2018, when he raised $38 million in three months on his way to very nearly knocking off Sen. Ted Cruz (R) in Texas, has had no breakout moment that can help separate him from 19 other Democrats running for president. So what’s different then and now? Here are some theories:

He didn’t get off to a good start: After losing to Cruz, O’Rourke went on a reflective journey. Literally. He set out on a solo road trip across the country and blogged about the people he met, his hopes for the future of his career and the country — and his dentist visits. He went on Oprah Winfrey’s show and met privately with former president Barack Obama. O’Rourke’s will-he-or-won’t-he run-for-president journey came across to some Democrats who were following it as self-centered. “Have been stuck lately,” O’Rourke wrote in one Medium post. “In and out of a funk.”

Most candidates have a deciding period on whether to run for president. (Donald Trump spent years going back and forth.) But most don’t document every thought they have about it on social media. In his Senate race, O’Rourke was the most successful candidate arguably ever in using social media to make a national name for himself. But after that race, he provided a cautionary tale of such fame: There’s such a thing in politics as too much sharing.

Mayor Pete: O’Rourke, 46, isn’t the only youngish, white man with a relatively thin political résumé from a conservative part of the country running for president. There’s not really a way to measure whether Pete Buttigieg, the 37-year-old mayor of South Bend, Ind., is drawing supporters away from O’Rourke. But it’s worth noting that in the very early days of the race, Buttigieg has captured the virality that O’Rourke had hoped for. In early April, Buttigieg was polling just below Joe Biden and Sen. Bernie Sanders (I-Vt.) in Iowa and New Hampshire, and he turned heads with an articulate performance at a CNN town hall last month. O’Rourke, as Johnson noted, is eschewing televised town halls for meeting voters in backyards.

He’s already had a high-profile gaffe: O’Rourke used to frequently joke on the campaign trail about being an absentee father. He said his wife, Amy, raises their three kids “sometimes with my help.” When O’Rourke started running for president, that joke blew up in his face. To a broader audience, critics found it made light of the gender imbalance inherent in child-rearing and exacerbated the perception that O’Rourke could afford to put career over family because he’s a white man. O’Rourke apologized for saying it and now regularly talks about white-male privilege. “As a white man who has had privileges that others could not depend on or take for granted, I’ve clearly had advantages over the course of my life,” he said in March.

Other 2020 candidates have had gaffes that break through the noise and earn headlines. (See: former vice president Biden making light of his physical contact with women that made some uncomfortable.) But O’Rourke has less margin for error than Biden.

Ted Cruz: One thing to consider is the backdrop by which voters are gauging O’Rourke. In 2018, he was running to unseat one of the most unpopular Republican politicians in the nation. The prospect of unseating Cruz in Texas of all places was exciting, so exciting that Democrats across the country with less-interesting races gave their money to O’Rourke. (O’Rourke raised as much in one quarter as some presidential candidates raise in entire campaigns, setting a fundraising record for a Senate race.)

This time, O’Rourke is not the only Democrat who has a chance to unseat an unpopular Republican politician. It’s possible that the candidate who looks good running against Cruz doesn’t look as great compared with one of the most talented and diverse fields of Democratic presidential candidates in recent memory running against Trump.

It’s early: Maybe O’Rourke isn’t catching fire yet because most Democratic primary voters don’t know for whom they’re going to vote. A new Post-ABC News poll asked Democratic and Democratic-leaning voters to name a candidate they support, and 54 percent of them said they didn’t have one yet.

That poll also suggests there’s room for O’Rourke to grow. Of the 20 candidates in the race, O’Rourke lands in the top six when asked which candidate Democrats are leaning toward, with 4 percent naming him, tying him with Sens. Kamala D. Harris (Calif.) and Elizabeth Warren (Mass.).

“He’s got all the basic tools,” Democratic strategist Jim Manley said of O’Rourke. “The question is whether he can reconnect again, like he did on the campaign trail against Cruz. … If I were his team, I’d be concerned about whether he can reach those highs again.”