Did US President Donald Trump's eldest son break US law in meeting a Russian lawyer he hoped would dish compromising dirt on the woman standing between his father and the White House? Could the 39-year-old real estate scion be charged with treason? This is what legal experts say about what is known so far of the June 2016 meeting in New York between Mr Donald Trump Jr and Ms Natalia Veselnitskaya.
What law might he have broken?
The most incriminating revelation, say experts, are the e-mails that Trump Jr dumped on his Twitter account: namely that he would "love" to hear what the Russian had to say about Mrs Hillary Clinton.
"If it's what you say I love it," he wrote back within minutes of being told the lawyer had information that would "incriminate" Mrs Clinton as "part of Russia and its government's support for Mr Trump".
Law professor Brandon Garrett of the University of Virginia says since Watergate, federal law has forbidden any direct or indirect foreign contribution or promise of such to a US election. The statute outlaws any donation "or other thing of value" which Prof Garrett said could potentially include information.
Another worry for Trump Jr is that conspiracy law is sweeping.
"One does not have to have committed a crime, the attempt is enough," said Prof Garrett.
But electoral law expert Daniel Tokaji of Ohio State University sees "very serious free speech" concerns and "troubling implications" in interpreting information as a "contribution". He warned it "could prohibit a campaign from gathering information about a rival campaign".
Law professor Susan Klein of the University of Texas and a Democrat, doesn't believe Trump Jr could be prosecuted just for talking either - "except perhaps if they paid for it or exchanged it for something". There has been no suggestion, at least so far, that happened. Who decides if there's a case?
The Federal Election Commission logically pursues election law violations, says Prof Tokaji. But split three-three between Democrats and Republicans, "it's very unlikely they would take action", he added.
In theory the US attorney's office in Manhattan, where the meeting took place, could also open a case.
More likely is that former FBI director Robert Mueller, the special prosecutor in charge of investigating possible links between the Trump campaign and Russia, will determine if there's a case, says Prof Tokaji.
Whether the electoral law has been broken or not, he believes it is still worth investigating.
"It is quite troubling... that someone possibly acting at the behest of a foreign power is colluding with people at the very top (of a presidential campaign)," he said. Did he commit treason?
Democratic Party lawmakers used the T word on Tuesday, but some experts doubted it would stick.
"Simply having a contact with a foreign country, even a foreign adversary - we are not at war - does not make it espionage or treason," says law professor Joshua Dressler of Ohio State University.
"To bring it within treason, you'd have to (show that) they intended to harm their own country... That's an extreme argument to make," he said. "It would probably have to be something less extreme." AGENCE FRANCE-PRESSE