According to an email that Donald Trump Jr. himself shared with the public, he was approached by one of his father’s former Russian business partners with an offer from a senior Russian government official to provide the Trump campaign with negative intel on Hillary Clinton. Trump Jr. replied “If it’s what you say I love it” and scheduled the meeting, inviting then Trump campaign manager, Paul Manafort, and his brother-in-law, who was advising the campaign, to join them. The meeting took place in June 2016 just after Donald Trump became the Republican Party’s nominee for president.

In the interview that follows, criminal law experts from Stanford Law School, Professors Robert Weisberg and David Sklansky, answer questions about the law and the meeting.

Was the meeting that Donald Trump Jr, Jared Kushner, and Paul Manafort had with a Russian national in and of itself illegal?

Sklansky: Being in the same room wasn’t illegal.  Whether the meeting was illegal depends on what was said and done—and on what the Trump people were trying to accomplish.

Weisberg: The mere fact of meeting was not illegal.

There has been some debate playing out in the media about a violation of 52 U.S. Code Section 30121 of our campaign finance laws. Can you talk about that?

Weisberg: There’s a plausible charge here but it would depend on a number of issues never resolved by a federal court: Most obviously, was the information he solicited a “thing of value?” Common sense says yes, but the closest precedents are in the area of the federal bribery laws, which suggest that while something “intangible” can be a thing of value, it has to have a fairly monetizable value. Information might be a thing of value if in effect it is the ‘deliverable” of some sort of expensive information-gathering or analysis service, but otherwise it’s dubious. The “willfully” term in the statute will leave Trump Jr.  with the not quite absurd but very weak argument that it requires proof that he knew of the terms of the criminal law at issue here.

Sklansky: That statute makes it illegal for foreign nationals to contribute to U.S. election campaigns, and illegal for anyone to solicit or receive a contribution to a U.S. election campaign from a foreign national.  The contribution can be of money or any “thing of value.”  It’s not entirely clear whether dirt on a political opponent counts as a “thing of value” for purposes of the statute.

Can you explain collusion and the legal requirements to meet that charge? What about conspiracy, coordination, and aiding and abetting? Can you help us understand potential charges?

Sklansky: “Collusion” isn’t a criminal law term, but in normal, everyday use, “collusion” usually means a secret agreement to cooperate illegally or improperly.  A secret agreement to cooperate illegally can, in fact, itself be illegal:  that’s the crime of conspiracy.  If two people agree to commit a crime—like, for example, receiving illegal campaign assistance from a foreign national—and then one or more of them does anything to carry out the agreement—like, for example, reserving a room for a meeting—then they’ve committed the crime of conspiracy.

Unlike conspiracy, “aiding and abetting” isn’t a separate crime.  Aiding and abetting is a way you can be guilty of a crime.  Basically, it’s a legal doctrine that says that if one purpose helps or encourages another person to commit a crime, both people are guilty of the crime.

Weisberg: Conspiracy to do what? Aiding and abetting what? There has to be an object crime or a crime by a principal being abetted. If there is a 52 sec. 30121 crime lurking, there can be a conspiracy to do that crime. There’s even an argument under federal precedent that if they agreed to do an act which is a civil violation of campaign finance regulations but not itself a crime, the agreement can still be a crime of conspiracy. Remember Oliver North of Iran-Contra? He was charged with conspiracy to violate the Boland Amendment, which was a congressional budget restriction.

Some have called for impeachment. Is impeachment purely a political process? What does the law say about that?

Weisberg:  It doesn’t say much of anything. “Political” is not a bad word. Here it just means that the articles of impeachment do not have to match a criminal statute (though they likely would), nor that the trial in the Senate has to meet the requirements of a  criminal trial. It’s really a super-nuclear vote of no confidence. A president “convicted” in the Senate (and hence removed) could not appeal to a court in the manner of a criminal defendant.

Sklansky: Impeachment is a quasi-legal, quasi-political process.  It’s legal in the sense that it requires a formal charge, by the House of Representatives, and then a trial in the Senate.  And the Constitution sets out the grounds for impeachment:  “treason, bribery, or other higher crimes and misdemeanors.”  But Congress is the sole judge of what counts as a “high crimes and misdemeanors,” so in practice that means that there is significant element of politics associated with the process.

Does the Trump Jr./Russian meeting fall into the remit of Robert Mueller’s investigation?

Sklansky: Absolutely.  The stated objective of Mueller’s appointment was “to ensure a full and thorough investigation of the Russian government’s efforts to interfere in the 2016 presidential election,” and Mueller was explicitly authorized to prove “any links and/or coordination between the Russian government and individuals associated with the campaign of President Donald Trump.”  So a meeting between senior officials of the Trump campaign and individuals purporting to act on behalf of the Russian government is squarely within the ambit of Mueller’s investigation.  It’s hard to think of something that would be more germane to what he has been asked to look into.

It’s also relevant that Trump and members of his campaign have repeatedly denied that they had any contact with Russian representatives in the run-up to the election.  Lying isn’t ordinarily a crime, but if they made representations like that on federal forms or under oath, it could be a crime.

Weisberg: You betcha.

Robert Weisberg is the Edwin E. Huddleson, Jr. Professor of Law and Faculty Co-Director of the Stanford Criminal Justice Center (SCJC). David Alan Sklansky, former federal prosecutor, is Stanley Morrison Professor of Law at Stanford Law School. He is also a faculty co-director of SCJC.