The release of Donald Trump, Jr.,’s e-mails regarding a meeting last June with a Russian lawyer, Natalia Veselnitskaya, show that, contrary to President Trump’s previous statements, representatives of his campaign were apparently willing to accept help from the Russians in order to win the election. This is obviously a political problem for the President and his Administration, but is it also evidence of criminal behavior?

“Collusion” is not a legal term in this context, nor is it a crime. Neither is listening to outlandish tales, even from foreigners. But Trump, Jr.,’s e-mails do raise questions of possible criminal behavior, starting with violations of campaign-finance laws. Federal law prohibits American campaign officials from soliciting from foreign governments “anything of value . . . in connection with” an election. In the meeting with Veselnitskaya, did Trump, Jr., or Jared Kushner, the candidate’s son-in-law, or Paul Manafort, then Trump’s campaign manager, who were also in attendance, solicit anything of value? The e-mails don’t clearly answer that question. But it is possible that they solicited information–perhaps specific information, relating to, say, e-mail accounts associated with Hillary Clinton’s campaign. Robert Mueller, the special counsel investigating Russian interference in the campaign, might conclude that such a solicitation could constitute a crime, and he might ask a grand jury to return an indictment on that theory. (The possibility of a prosecution based on an “anything-of-value” theory has been explored in greater detail by Robert Bauer, President Obama’s White House counsel, and by Rick Hasen, an election-law specialist, in several posts.)

But this narrow view of one meeting fails to provide a full picture of how prosecutors approach criminal investigations. There are thousands of e-mails between members of Trump’s campaign for investigators to examine. Do any of those messages say anything about the meeting? Are other meetings with Russians described in them? In some respects, the person most exposed by the released e-mails is not Trump, Jr., but Jared Kushner, who continues to serve as a high-ranking White House adviser. More to the point, under penalty of law, Kushner filed an application to receive a security clearance, which was supposed to list all his foreign contacts. He did not initially disclose the June meeting, and congressional Democrats have been calling for his security clearance to be revoked. Inadvertence and bad memory are valid defenses in false-statement cases, but could Kushner seriously contend that a meeting set up with an e-mail heading “Russian – Clinton – private and confidential” simply slipped his mind?

Certainly the attendees at that meeting, as well as other Trump campaign officials, will be asked by F.B.I. agents, and perhaps before a grand jury, about contacts with the Russians. Any sort of false statement in these contexts would be a federal crime. Federal law also bars the kind of hacking that was visited upon John Podesta, Clinton’s campaign chairman, and the Democratic National Committee; if any Trump officials aided and abetted the hacking, that, too, would be a crime.

In addition to those concerns, there are other legal issues at stake. In the broader subject of obstruction of justice, the President’s decision to fire James Comey, the former director of the F.B.I., will be central to Mueller’s inquiries. If Mueller decides to go further afield into Trump’s financial matters, there are possible violations of the Foreign Corrupt Practices Act, especially relating to the Trump hotel in Azerbaijan. (See Adam Davidson’s story on the subject.) In white-collar cases, federal prosecutors also frequently make use of the broadly worded statute barring money laundering.

Then there is the matter of espionage, in which Trump associates could possibly have been victims as well as accomplices. Shortly after the election, Kushner, a novice in government, allegedly set up a back channel to communicate with the Russian government, using communication facilities operated by the Putin regime. At a minimum, this is deeply naïve on Kushner’s part; whether something more sinister was afoot is worthy of investigation. In total, the newly disclosed Trump, Jr., e-mails do not prove that any crimes were committed, but they make Mueller’s to-do list even longer.