Drop the Foreign Agent inquiry into RT and Sputnik. It will potentially increase the threat and have no practical effect, but not because of the reasons commonly heard. The designation should have been automatic, but the delay in deciding to investigate RT and Sputnik will only result in a pyrrhic "victory."
With the recent news that the FBI may be looking into whether Sputnik should have registered under FARA, you may be interested in this article I wrote over 2 years ago on RT and FARA. The article applies equally to Sputnik. The bottom line of FARA can really be stated like this: truth in advertising, or, know your source.