Tucker Carlson has often shown much bias in his reporting and opinions. It has now been reported that a Russian internal memo shows that they too consider him a good 'asset' because he is the western voice who echoes the Russian sentiments. It is interesting to note that he is the only westerner mentioned in this memo in this context. now that RT America has ceased operations of all live programming, what are the chances of the US government sanctioning Tucker Carlson and can it actually be done?
The first amendment to the US constitution says:
Congress shall make no law [...] abridging the freedom of speech, or of the press; [...]
This constitutional hurdle is a very high obstacle to preventing the media from publicly saying something that is detrimental to the interests of the US government. Giving people the freedom to say "our government is wrong" without being afraid of repercussions is the reason why this amendment exists. And yes, freedom of speech includes the freedom to be wrong. When someone makes false claims in public to sway public opinion, then it's the responsibility of their peers to point out those falsehoods and let people decide by themselves who to believe. The government can of course also engage in counter-speech, for example by holding a press conference where they address claims made about them and present their side of the debate. But it is not the job of the government to use force to suppress falsehoods, because the government can not be expected to be impartial in this matter.
The government not suppressing public discourse is one thing which separates libertarian states like the United States from authoritarian states where uncomfortable speech is suppressed.
There are a couple exceptions. But as long as Carlson doesn't make any statements which are defamatory, obscene, fraudulent, violate copyrights or explicitly incite physical violence, the government's hands are tied.
what are the chances of the US government sanctioning Tucker Carlson and can it actually be done?
The memo does not allege collusion with Russia or any other foreign power, or working as its agent, either of which requires registration. Independent expression of views sympathetic to another country prominent enough to gain the other country's attention in connection with a media platform is not actionable or sanctionable under U.S. law under the 1st Amendment. It might, however, prompt an investigation by legal means to determine if he was, in fact, an unregistered Russian agent.
The analysis would change slightly if the U.S. declared war on Russia, but only slightly so and still probably wouldn't justify action without a more targeted basis for it.
I suspect that the legal threshold for such sanctions is very high. This is not surprising, given that the freedom of expression is an acknowledged value in the US: one can express whatever views they want, as long as it doesn't pose a direct threat to the national security. Since Tucker Carlson is not a government official, his personal opinions are unlikely to affect anything but how people vote (and even this is doubtful, given the degree of voter polarization in the US).
It is also worth looking at the historical examples: all kinds of Communist and Soviet sympathizers were common in the Cold War era, and certainly were a tool of political influence used by Moscow. Yet very few of them were legally sanctioned, unless they engaged in open espionage. True, some lost jobs through McCarthyism - but these are not legal sanctions. Moreover, there are many high-profile examples who hardly ever suffered from their communist sympathies, such as Bernie Sanders (who studied Marx and campaigned for a communist party as a young man, as he acknowledges) or Angela Davis (twice a vice-presidential candidate for the American Communist party, who openly entertained contacts with high-profile Soviet and East German officials).
In 1971, the CIA estimated that five percent of Soviet propaganda efforts were directed towards the Angela Davis campaign. In August 1972, Davis visited the USSR at the invitation of the Central Committee, and received an honorary doctorate from Moscow State University.
On May 1, 1979, she was awarded the Lenin Peace Prize from the Soviet Union. She visited Moscow later that month to accept the prize, where she praised "the glorious name" of Lenin and the "great October Revolution".
Finally, it is worth bringing up the term useful idiot (usually attributed to Lenin):
In political jargon, a useful idiot is a derogatory term for a person perceived as propagandizing for a cause without fully comprehending the cause's goals, and who is cynically used by the cause's leaders.
I do not intend to insult anybody, but merely pointing out that political positions in opposition to the government, can be often used by the enemies of the country.
Others have already pointed out the First Amendment issue, but I would also like to point out a potential Fifth Amendment issue (with the disclaimer that I'm not a lawyer):
No person shall be held to answer for a capital, or otherwise infamous crime, unless on a presentment or indictment of a Grand Jury, except in cases arising in the land or naval forces, or in the Militia, when in actual service in time of War or public danger; nor shall any person be subject for the same offence to be twice put in jeopardy of life or limb; nor shall be compelled in any criminal case to be a witness against himself, nor be deprived of life, liberty, or property, without due process of law; nor shall private property be taken for public use, without just compensation.
You're not too specific about what you mean by "sanctions," but I assume that you mean sanctions similar to ones that have been imposed on Russian Oligarchs. In any case, it's hard to imagine any specific sanction that would not result in Tucker Carlson being deprived of "life, liberty, or property". That being said, since he's a U.S. citizen, the only way they could do this is by him being convicted of a crime.
Reporting in a biased way and expressing opinions that the government doesn't like are not crimes. Therefore, they cannot deprive him of life, liberty, or property.