Donald Trump Jr. stands onstage with his father, Republican presidential nominee Donald Trump, after Trump’s debate against Hillary Clinton at Hofstra University in Hempstead, N.Y., in September. (Brian Snyder/Reuters)

Donald Trump Jr.’s willingness to accept incriminating information about Hillary Clinton — even when he was told the material was “part of Russia and its government’s support” for his father — could put him or others in legal jeopardy, though investigators would probably have to do more work to substantiate criminal charges, analysts said.

When Trump Jr. released emails showing how he arranged to meet with a Russian lawyer, he probably showed to the world a key piece of evidence in the investigation of whether his father’s campaign coordinated with Russia to influence the 2016 election.

The emails show that the meeting was initiated when a British-born publicist emailed Trump Jr. claiming a Russian government lawyer had offered to help Trump Jr. obtain “some official documents and information that would incriminate Hillary and her dealings with Russia and be very useful to your father.”

“This is obviously very high level and sensitive information but is part of Russia and its government’s support for Mr. Trump,” the publicist wrote.

(Peter Stevenson/The Washington Post)

Trump Jr. wrote back that if the information was as promised, he would “love it,” and he and the publicist soon began to discuss logistics of a meeting. Eventually, the emails were forwarded to Jared Kushner, the candidate’s son-in-law and close adviser, and then-Trump campaign chairman Paul Manafort.

Legal analysts said the exchange is evidence that Trump Jr., and possibly the others, might have violated campaign finance law, defrauded the U.S. government or both — though the case is far from a slam dunk.

In July 2016, then-candidate Trump said he welcomed help from Russia to find and release 30,000 of his opponent’s emails which had been deleted. It is not clear whether that remark was a campaign trail quip, rather than a serious request to damage Clinton through nefarious means. Analysts said Trump Jr.’s emails, though, seem to show a real willingness to at least entertain the Kremlin’s help.

“The emails tell me that he’s aware that the Russian government is trying to influence the election in favor of Trump, and they also indicate an intent, at least on the part of Donald Trump Jr., to entertain the idea of working with the Russians in their efforts,” said Barak Cohen, a former federal prosecutor now in private practice at Perkins Coie. “It raises a number of potential areas of liability.”

In the United States, it is illegal for foreign nationals to donate things of value in connection with an election, and it is similarly illegal for people to solicit or accept a contribution or donation from a foreigner. In this instance, prosecutors could possibly make a case that the information being offered was a thing of value coming from a foreign national, legal analysts said.

Such cases are not common, but they are also not unheard of. In the mid-1990s, the Justice Department launched an investigation into possible improper campaign contributions that originated from China flowing into President Bill Clinton’s reelection campaign. The case resulted in guilty pleas among those involved in some illegal contributions, but it never produced charges against any officials at the White House, the Democratic National Committee or the Bill Clinton campaign.

Charlie Spies, a campaign finance lawyer at Clark Hill who advises GOP candidates and groups, said pondering such a case against Trump Jr. would be a stretch.

“A few, unhinged liberal lawyers have put forth the theory that there’s a campaign finance violation, but there is zero precedent or legal authority to back up that claim,” Spies said. “Based on public information, the conversation regarding potential negative information did not meet the standard for a solicitation, and also does not have a provable value, which would be necessary in a campaign finance context.”

Analysts said prosecutors might also use Trump Jr.’s email as evidence of another possible criminal charge: conspiracy to defraud the United States. The law in that area is broad, essentially requiring investigators to prove a conspiracy to undermine a government function.

The latest revelation “certainly advances the ball way down the field” toward such a case, said Peter Zeidenberg, a former federal prosecutor who worked as deputy special counsel in the prosecution of Lewis “Scooter” Libby over the leak of an undercover CIA agent’s identity.

“At the very least, it shows an intent and interest to traffic in this information,” Zeidenberg said.

Trump Jr.’s emails, importantly, make no reference to any Russian hacking of the DNC or Hillary Clinton campaign chairman John Podesta’s emails. At the time they were sent, the hacking had not been publicly reported.

In a statement, Trump Jr. said he thought the information he could potentially receive was “Political Opposition Research” — which is common in political campaigns, albeit not from foreign government sources.

Acceptance of mere opposition research, Cohen said, might not qualify as “undermining the election process,” if the information was not illegally obtained.

The White House has pointed to a report in Politico saying Ukrainian government officials “helped Clinton’s allies research damaging information on Trump and his advisers.”

Randall Eliason, a former federal prosecutor who teaches law at George Washington University, said the facts as they stand are not enough to build a criminal case against Trump, though they might be a start.

“You need evidence of what was actually said at that and other meetings, what actual agreements were actually reached, and if any Trump campaign people participated in any way about the timing of email releases or the hacking itself,” he said.

Analysts said investigators would probably want to question Trump Jr., as well as Kushner and Manafort, about the substance of the encounter and about any follow-up conversations. All three, analysts said, could be in trouble.

Trump Jr. has said the meeting amounted to nothing. The Russian lawyer with whom he ultimately met — Natalia Veselnitskaya — has said she was not working on behalf of the Russian government. A Kremlin spokesman denied knowing who she is.

According to Trump Jr.’s account of the conversation, Veselnitskaya was largely focused on the Magnitsky Act, which imposed sanctions on Russian officials responsible for the death of a Russian lawyer investigating fraud in the Kremlin, and her information on Clinton was not useful.

But Trump Jr.’s explanations on the topic have shifted as the New York Times has reported new details. And if his description of the meeting was not accurate — and Veselnitskaya had offered damaging information in exchange for an official benefit, such as sanctions relief — the case against him could escalate quickly, analysts said.

“If there’s an actual quid pro quo,” Zeidenberg said, “that would be a smoking gun.”