What Is a Quid Pro Quo?

Was there a quid pro quo involved in President Trump’s demand that Ukraine open investigations that he thought could benefit him politically, including one into former Vice President Joseph R. Biden Jr. and his son Hunter?

The president has denied there was any quid pro quo, but Michael Mulvaney, the acting White House chief of staff, undercut that denial at a news conference on Thursday. Then he backpedaled, issuing a statement that repeated Mr. Trump’s claim there had been no quid pro quo.

Which raises the question: What is a quid pro quo?

For those who do not speak Latin or who may be unacquainted with legal terminology, the basic concept behind “quid pro quo” can be summed up in a more colloquial saying in English: If you scratch my back, I’ll scratch yours.

“Quid pro quo is Latin for ‘thing for thing,’” Paul Butler, a professor at Georgetown University Law Center, said.

It means giving someone something he or she wants, but only if that person gives you what you want.

“The thing about a quid pro quo,” Professor Butler added, “is it makes the conduct look like a shakedown.”

The public so far knows of a few possible quid pro quos that may have been involved in the dealings between Ukraine and Mr. Trump and his associates.

One involved $391 million in military aid to Ukraine, which has been battling Russian-backed separatists since 2014.

Mr. Trump froze those funds after they were approved by Congress. Then, in a July 25 phone call, he asked the Ukrainian president, Volodymyr Zelensky, to open an investigation into Mr. Biden’s son and another into a theory about Ukrainian interference in the 2016 election. That theory has been debunked by the F.B.I. and CrowdStrike, the California cybersecurity company that investigated Russian hacking of the Democratic National Committee’s emails in 2016.

On Thursday, Mr. Mulvaney became the first White House official to publicly say the release of military aid was connected in part to Mr. Trump’s political demands. But he did not use the term “quid pro quo.” Later in the day, he released a statement denying that any quid pro quo existed.

The look back to what happened in 2016 certainly was part of the thing that he was worried about in corruption with that nation,” Mr. Mulvaney told reporters earlier in the day, referring to Mr. Trump. “And that is absolutely appropriate.”

He said Mr. Trump was also interested in claims that Ukraine had interfered in the election by allowing a Democratic National Committee computer server to be hidden in the country.

“Did he also mention to me in passing the corruption related to the D.N.C. server? Absolutely. No question about that,” Mr. Mulvaney said. “But that’s it, and that’s why we held up the money.”

Quid pro quos can be seen in bribery, extortion and sexual harassment cases, said Richard Briffault, a professor at Columbia Law School. They are not always illegal, he explained, but when talking about politics it often means a corrupt exchange.

“It gets at the idea of a corrupt deal,” Professor Briffault said. And it doesn’t always have to be explicit. There is “the concept of winks and nods,” he added.

“A quid pro quo can be established if under the circumstances, it’s clear that’s what happening,” he said, adding that unusual timing or behavior could provide the basis for evidence that a corrupt exchange happened.

The term is important in both criminal and civil cases, said Professor Butler, a former federal prosecutor who specialized in public corruption cases.

“Federal bribery prosecutions are the legal case in which quid pro quo comes up the most,” he said. “That would be a criminal case. In civil law, sexual harassment is a context in which quid pro quo would come up.”

The Justice Department did not respond to email messages on Thursday asking for an official definition of “quid pro quo.” Nor did the office of Letitia James, New York’s attorney general.

Two recent cases in New York that involved a quid pro quo were the prosecutions of the state lawmakers Sheldon Silver and Dean G. Skelos.

Mr. Silver, the former speaker of the New York Assembly who was convicted in 2018 on federal corruption charges, made millions by awarding and directing funds to a cancer researcher, Robert N. Taub at Columbia University, and to two real estate developers.

Professor Briffault pointed to Mr. Silver’s scheme as a classic quid pro quo: Mr. Silver, a Manhattan Democrat, supported Mr. Taub’s research, and Mr. Taub, in return, sent clients to a law firm that gave Mr. Silver money.

For Mr. Skelos, the former New York State Senate majority leader who was also convicted of corruption in 2018, the exchange involved his son.

Mr. Skelos, a Long Island Republican, pressured business executives into giving his son about $300,000 for jobs he rarely showed up for. During the trial, prosecutors said that if the executives didn’t pay up then Mr. Skelos would kill legislation their firms were seeking.

“In many of these cases, the key thing is the ‘pro’,” Professor Briffault said. “Why did you do this thing? Did you do it for a legitimate reason? Did you do it for a corrupt reason?”