'Stench of bribery and treason’: Legal expert points to Don Jr’s Russia meeting as ‘proverbial smoking gun’

A constitutional law expert said Donald Trump Jr.'s meetings with a Russian attorney were "the proverbial smoking gun" in a criminal conspiracy -- and he said there's no way the president wasn't involved.

Laurence Tribe, a professor of constitutional law at Harvard University, reacted Tuesday morning to news reports that Trump Jr. received an email notifying him that the Kremlin-linked lawyer he later met with had damaging information about Hillary Clinton that was gained as part of a Russian government effort to aid his father's campaign.

"We now have the proverbial smoking gun: TJr was part of criminal conspiracy to violate fed crim laws banning foreign aid to any US campaign," Tribe tweeted.

Trump Jr. admits to meeting with the attorney, along with brother-in-law Jared Kushner and then-campaign chairman Paul Manafort, in hopes of obtaining damaging information, and she asked for U.S. sanctions to be lifted on some of her human rights abuser clients.

"Offering to help Putin weaken Magnitsky Act's anti-Kremlin sanctions in return for Putin's help vs Hillary has stench of bribery & treason," Tribe said.

Trump was in New York City on June 9, 2016, meeting with Manafort, then-RNC chair Reince Priebus, Gov. Chris Christie, then-campaign manager Corey Lewandowski and others at Trump Tower -- where his son met that same day with the Russian attorney.

Tribe agreed that no prosecutor or defense attorney would believe Trump was unaware that his son, son-in-law and campaign chairman were meeting in the same building with a foreign agent to discuss his campaign.

"If he DIDN'T know, that makes Sec 4 of the 25th Amendment seem even more salient!" Tribe said.

Tribe said it likely was only a matter of time before reports revealed that Trump knew about the meeting -- which he said was already grounds for impeachment.

"That door's wide open now," Tribe said. "The big Q is which GOPer will be the first to step over the threshold, when that'll happen, and how to analyze it."