At El Chapo Trial, a Potential Star Witness: El Chapo - The New York Times

[What you need to know to start the day: Get New York Today in your inbox.]

Usually, following the end of a long day in the drug trial of Joaquín Guzmán Loera, the Mexican kingpin known as El Chapo, the courtroom empties slowly.

But last Tuesday, most reporters rushed out at the end of proceedings to file the stunning news in testimony from Alex Cifuentes Villa, a former lieutenant in the Sinaloa cartel, who said that former Mexican president Enrique Peña Nieto had accepted a $100 million bribe from Mr. Guzmán in 2012.

So it was in a mostly empty courtroom that prosecutors asked Jeffrey Lichtman, one of Mr. Guzmán's defense attorneys, to turn in his official witness list.

The defense responded that they were unprepared to turn in a finalized list, but they did have two names they wanted to be sure the prosecution knew about. The first was a witness (not identified by name) who was in the government's custody. Then, Mr. Lichtman walked toward the judge, bent forward and in a low voice mentioned one more name — the defendant's.

The addition signaled what had been rumored for weeks: The drug kingpin might want a shot at telling his own story in Federal District Court in Brooklyn. It would be yet another startling development in a trial that has already delivered many sensational moments.

Mr. Lichtman has told reporters it is only a "possibility" that Mr. Guzmán might testify.

"It's his absolute right to testify or not to testify," another of his attorneys, A. Eduardo Balarezo, said in an interview.

The next day, Mr. Guzmán's attorneys were talking to the defendant about the possibility of testifying, although those discussions were described as more theoretical rather than tactical. Mr. Guzmán's attorneys declined to give details of those conversations, citing attorney-client privilege.

Giving Mr. Guzmán the floor might be a good idea, said Bruce Cutler, a bullishly upbeat defense attorney who describes his own tactics as a "let it all hang out approach" and who won acquittals three times in the 1980s and early 1990s for John Gotti Sr., who law enforcement officials had said was the head of the Gambino crime family. (Mr. Cutler and Mr. Lichtman, who describe each other as friends, worked together for some time, both working on Gotti family cases.)

"Why not go for broke?" Mr. Cutler asked. "What's the pitfall? What's going to happen? I mean it's unusual but maybe that's what you need. The playbook says don't do it unless you have to. And I think maybe in this case you have to. So I say, 'Viva El Chapo!'"

In a "show trial" like this one with intense security measures and a plethora of witnesses, Mr. Cutler said the defense has to mount a show of their own.

"Trials like this are never won, unless — unless — you do something unusual," he said.

Mr. Guzmán might not have much to lose. In nearly three months of testimony, prosecutors have used Mr. Guzmán's former associates, law enforcement officials and secretly recorded phone calls and text messages to exhaustively paint him as a vindictive, murderous criminal who led the largest drug trafficking organization in North America.

"He may feel that it's a foregone conclusion that he will be convicted," said Bruce Green, a professor at Fordham Law School who specializes in legal ethics and criminal procedure. "And the testimony that he wants to give may not be to get the jury to acquit him but rather to establish his place in history and to explain himself to the world."

Preparing Mr. Guzmán for the stand would take time, and Mr. Balarezo said such preparation had not yet begun.

"Any client who testifies obviously has to be advised of the possible consequences of testifying," Mr. Balarezo said. "And has to be prepared to face cross-examination."

Mr. Guzmán's possible testimony could come soon. Prosecutors told the judge earlier this week they expect to rest their case by Jan. 28 at the latest. Afterward, the defense will mount its own case.

Mr. Guzmán's testimony, if it happens, would be likely to extend the trial by a week or more since he'd have many details to offer and the cross-examination would probably be lengthy.

Mr. Lichtman said he was treating Mr. Guzmán like any other client, adding that he always listed his clients as potential witnesses in order to keep the opportunity open.

"I don't want to be foreclosed down the line," he said.

From the start of the trial, the defense has peddled the narrative of Mr. Guzmán's impoverished upbringing, how as a child he sold oranges in the streets just to scrape by. Hearing Mr. Guzmán's story from his own mouth could humanize him in the eyes of the jury — or at least, appeal to his own flair for dramatics. After all, Mr. Guzmán once wanted to direct a movie about his own life, and later met with the actors Kate del Castillo and Sean Penn in another attempt to share his story.

"If the defendant doesn't testify, you can take the shards of evidence and try to piece together a story that establishes reasonable doubt," Mr. Green said. "But once the defendant testifies, the jury chooses between two stories: the prosecution's story and the defendant's story."

Often, defendants interested in sharing their story are dissuaded from doing so by their attorneys, who fear the prosecution would be able to punch holes in whatever account they tell. However, Mr. Guzmán's situation appears remarkable.

"In this case," Mr. Green said. "It's hard to imagine that there's much that's more powerful than what the prosecution has already produced."