Former Texas Senate candidate Beto O'Rourke faced across-the-board criticism on Tuesday after an unflattering interview in The Washington Post portrayed him as equivocal and unsure on a variety of substantive policy issues -- and included a comment that seemed to question the modern-day relevance of the U.S. Constitution.

O'Rourke, 46, is widely considered a possible 2020 presidential contender, after falling only a few percentage points shy of dethroning incumbent Texas GOP Sen. Ted Cruz in the 2018 midterm elections. But his relative lack of experience and expertise has emerged as a central objection to his prospective candidacy.

Speaking in El Paso, Texas, O'Rourke added fuel to those concerns by repeatedly demurring when asked for a direct answer on his positions on everything from visa overstays to whether President Trump should withdraw military forces from Syria.

And at one point in the two-hour chat with The Post's Jenna Johnson, O'Rourke openly wondered whether the U.S. can "still be managed by the same principles that were set down 230-plus years ago" in the Constitution.

The comment drew harsh rebukes on Twitter.

"This may make it difficult to take any future oath of office to 'preserve, protect and defend the Constitution,'" Rep. Liz Cheney, R-Wyo., wrote.

The article even included an apparent shot by at O'Rourke from former Illinois Democratic Rep. Luis Gutierrez, who told The Post he was “very pleasantly surprised” that O'Rourke -- who represented a mostly Hispanic district during his three terms in the House of Representatives -- was "suddenly interested" in immigration reform efforts last year.

Asked what could be done about illegal immigrants who overstayed their visas, O'Rourke told Johnson simply, “I don’t know."

MSNBC'S BRIAN WILLIAMS MOCKS O'ROURKE FOR INSTAGRAMMING TRIP TO THE DENTIST

Asked about the planned Syria pullout, he responded that there should be "a debate, a discussion, a national conversation about why we’re there, why we fight, why we sacrifice the lives of American service members, why we’re willing to take the lives of others. ... There may be a very good reason to do it. I don’t necessarily understand — and I’ve been a member of Congress for six years. ... We haven’t had a meaningful discussion about these wars since 2003.”

Asked whether the U.S. is capable of change, O'Rourke was again equivocal: "I’m hesitant to answer it," he said, "because I really feel like it deserves its due, and I don’t want to give you a — actually, just selfishly, I don’t want a sound bite of it reported, but, yeah, I think that’s the question of the moment: Does this still work? Can an empire like ours with military presence in over 170 countries around the globe, with trading relationships . . . and security agreements in every continent, can it still be managed by the same principles that were set down 230-plus years ago?”

Johnson, who said she spent two hours in all with O'Rourke on a tour of the border, said her interview revealed that the potential 2020 contender has an apparent preference for questioning rather than answering.

"When it comes to immigration policy and changing the way things are, he has few solutions — and would rather debate and discuss the topic," Johnson wrote on Twitter.

Other commentators were less forgiving.

"This last bit – where he suggests we might need to ditch the Constitution? – is wild," wrote senior Huffington Post political reporter Kevin Robillard.

"In WaPo interview, Beto O'Rourke displays striking lack of knowledge about immigration. Just knows one thing: He's against a wall," Washington Examiner chief political correspondent and Fox News contributor Byron York wrote on Twitter.

"Beto might have to figure out what he thinks about Syria before the first debate," commented CNN political reporter Rebecca Buck.

O'Rourke will have another opportunity for a major interview on the national stage in just a matter of weeks -- with talk show host Oprah Winfrey, as part of "Oprah's SuperSoul Conversations from Times Square" on Feb. 5.

He'll speak to Winfrey one-on-one as part of an event featuring others, including actors Bradley Cooper and Michael B. Jordan.

In the meantime, O'Rourke has been visible --- and some critics say, perhaps too visible -- on Instagram Live.

"So, I'm here at the dentist," the former Democrat congressman said with a giggle during a teeth-cleaning seen live on the service last week, before quizzing the dental hygienist about life along the U.S.-Mexico border. ( "Thank God this wasn’t Beto’s day to see the proctologist," MSNBC anchor Brian Williams joked, quoting online reactions to O'Rourke's stream.)

Influential activists in Iowa and elsewhere are clamoring for Beto to get in the presidential race, and The Post's article noted that numerous onlookers interrupted their interview with him to urge him to run.

"They're not going to wait forever," Mark Jones, a political science professor at Rice University in Houston, said of Democratic campaign operatives, donors, activists and fellow politicians looking to pick sides or offer endorsements. "The more candidates who start to formally launch their candidacies, the greater the pressure will rise on Beto."

Massachusetts Elizabeth Warren announced on New Year's Eve that she'd formed a presidential exploratory committee, hoping to get an early jump on people such as O'Rourke, former Vice President Joe Biden and Sens. Corey Booker of New Jersey, Bernie Sanders of Vermont and Kamala Harris of California.

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Although O'Rourke has not yet entered the 2020 fray, his influence on the race so far has been apparent. In a move that channeled O'Rourke and New York Democratic Rep. Alexandria Ocasio-Cortez, Warren broadcast herself in her kitchen on New Year's Eve using Instagram Live, drinking a beer and thanking her husband for his presence.

But O'Rourke's appeal proved difficult to properly emulate. On Sunday, following a range of negative reactions to Warren's broadcast on social media, President Trump dubbed the stilted encounter "Elizabeth Warren's beer catastrophe."

Fox News' Alex Pappas and The Associated Press contributed to this report.