Sam Nunberg, a former Trump campaign aide, appears on MSNBC's “The Beat With Ari Melber” on Monday evening. Nunberg later said that a lawyer who appeared on the same show helped persuade him to comply with special counsel Robert S. Mueller III’s subpoena. (MSNBC/The Beat with Ari Melber)

Former Trump campaign aide Sam Nunberg said Tuesday that he plans to comply with special counsel Robert S. Mueller III’s subpoena, an abrupt turnabout from just 24 hours earlier, when Nunberg publicly defied the Justice Department in an extraordinary day-long media blitz.

In a brief interview Tuesday with The Washington Post, Nunberg said he plans to comply with Mueller’s subpoena — part of the probe into Russian interference in the 2016 presidential election — and had changed his mind after receiving public and unsolicited advice from Maya Wiley, a lawyer with whom he appeared on Ari Melber’s MSNBC show Monday evening.

“She’s very, very smart,” Nunberg said of Wiley, New York Mayor Bill de Blasio’s former chief counsel. “She made a compelling case to me, and the case was that they have to do this for their investigation, and it was a fair point.”

Nunberg began his media whirlwind Monday with The Post, declaring, “Let him arrest me” as he explained why he did not plan to hand over emails and other documents related to President Trump and nine current and former Trump advisers, material that Mueller had requested.

But by the time Nunberg appeared on Melber’s show Monday evening, his behavior had grown increasingly erratic — captivating observers from West Wing aides to members of the media, and alarming some of his friends, who called him and begged him to stop. 

Nunberg appeared on the show with Wiley as another panelist. Wiley several times spoke directly to him, seeming to offer free legal advice. Addressing a concern of his, she said he was not protecting his self-described mentor, Roger Stone, by refusing to cooperate, and she urged him to “go testify.”

When Nunberg said the subpoena was costing him 80 hours of time as he tried to sort through the materials Mueller had requested, Wiley interjected, somewhat incredulously: “You’d rather spend possibly a year in jail than 80 hours going through documents?”

“I think your family wants you home for Thanksgiving, and I think you should testify,” she said at another point. 

By Tuesday morning, Nunberg seemed to have come around to her viewpoint.

Told that Nunberg said Wiley was the reason he had changed his mind, the lawyer laughed and said she was happy that he seemed to be following better legal advice now. “If it encouraged him to go to speak to his attorney, I am happy we prevailed upon him a more rational path,” Wiley said. “I did not think it was going to be a therapy session, but I think it became a therapy session.”

Echoing a sentiment Nunberg expressed — that he was frustrated by what he viewed as Mueller’s overly cumbersome request, which he said was causing him to fall behind on his other work — Wiley said that Nunberg “was in a difficult position and had not thought it through.”

“I don’t consider [it] as giving him legal advice,” she said. “I was just pointing out some of the errors in his thinking.”

But, she added, Nunberg could change his mind yet again: “With Sam, one needs to pay attention hour by hour.” 

Nunberg, a top political staffer for Trump in the run-up to the campaign, was fired in 2015 for racially insensitive Facebook posts and has since existed on the fringes of Trump’s orbit as a consultant. White House officials attacked his credibility Monday and characterized his media appearances as unhinged.

Tuesday, after explaining why he’d reversed himself, Nunberg said he had to end the interview: He didn’t have time to chat, he said, because he was busy working his way through Mueller’s request.

Philip Rucker contributed to this report.