After President Trump's oldest son tweeted out email correspondence in which he actively sought damaging information about Hillary Clinton offered by the Russian government, Democrats quickly called foul – and some even raised the possibility that these actions could be considered treasonous.

"Nothing is proven yet, but we’re now beyond obstruction of justice in terms of what’s being investigated," Democratic Sen. Time Kaine of Virginia said. "This is moving into perjury, false statements and even into potentially treason."

Rep. Seth Moulton of Massachusetts added: "If members of the administration are essentially conspiring with Russia… that’s the definition of treason," Moulton said. "This is a very, very serious affair."

Trump Jr. may be legally vulnerable on some fronts – after all, a special counsel and multiple congressional panels are investigating potential collusion between the Trump campaign and Russians who sought to influence the election by hacking Democrats. And a liberal watchdog group has already asked the Federal Election Commission and the Department of Justice to investigate whether campaign finance laws – which prohibit a non-citizen from giving, or promising to give, anything of value in hopes of influencing an election – were broken in the Trump campaign's meeting with Kremlin-linked lawyer Natalia Veselnitskaya.

But treason is a whole other level, legal analysts say.

First, treason in United States has a narrow definition in the Constitution. Here's what it says in Article III, Section 3:

Treason against the United States, shall consist only in levying war against them, or in adhering to their enemies, giving them aid and comfort. No person shall be convicted of treason unless on the testimony of two witnesses to the same overt act, or on confession in open court. The Congress shall have power to declare the punishment of treason, but no attainder of treason shall work corruption of blood, or forfeiture except during the life of the person attainted.

Russia, as legal experts have noted, is formally at peace with the United States, so any actions taken with Russia would not technically be considered treasonous.

"Russia is a strategic adversary whose interests are frequently at odds with those of the United States, but for purposes of treason law it is no different than Canada or France or even the American Red Cross," Carlton Larson, a law professor at the University of California at Davis, wrote in an op-ed for the Washington Post in February. "The details of the alleged connections between Russia and Trump officials are therefore irrelevant to treason law."

This line of thinking was shared by other legal experts following Trump Jr.'s email release.

CNN legal analyst Paul Callan said while the latest revelations suggested a clear link between the Russian government and Trump associates, it was too early to say whether it was even criminal, let alone treason.

Calling it treason was "absurd," he said.

"It just doesn't rise to that level," he said on CNN.

What's more, accusations of treason shouldn't be leveled lightly. Under the U.S. code, the punishment for treason is five years in prison, a fine of no less than $10,000, or death. Those convicted of treason also would not be able to hold any office in the United States.

Treason cases are very rare in the United States. According to the National Constitution Center, there have only been about 30 cases since the founding of the country. It has been 55 years since the last time someone was convicted of treason. In 1952, Tomoya Kawakita, a Japanese-American citizen, was sentenced to death for "brutally" abusing American prisoners of war while he was in Japan during World War II.

Kawakita wasn't executed, though. President Eisenhower commuted his sentence to life imprisonment plus a fine, and a decade later, President Kennedy ordered Kawakita be released from prison and banned from ever returning to the country.

Within the last 20 years, questions of treason have been raised at least twice over high profile cases: John Walker Lindh, the American-born man captured as an enemy combatant during the 2001 U.S. invasion of Afghanistan, and Edward Snowden, the former National Security Agency contractor who leaked U.S. surveillance programs.

Though Lindh faced 10 federal charges before a grand jury, treason was not among them.

As for Snowden, federal prosecutors charged him with violating the Espionage Act, but has been in asylum in Russia since 2013.

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