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.