I know that nothing much can be done about citizens repeating dangerous Russian propaganda on social media sites. Even when it is transparently obvious that a source is beyond dubious, and is actually completely fallacious and is intended entirely for the benefit of Russia and is intended to damage the West... If someone repeats it, there is not much we can do. (Assuming that that person genuinely, authentically believes this lie to be the truth)
However, what can be done about elected officials that do the same thing, or make public statements that promote nutty conspiracy theories that originate with Russian intelligence/disinformation services? Eg. Rep Nunes? I mean, when an elected official is essentially taking the side of Russian operatives who are spreading propaganda and lies... what exactly can be done about this? Just wait and hope the voters catch on? What we have now is effectively Russian propaganda agents who are elected as US Representatives. This gives a cachet to their lies, and helps members of the regular public accept these lies.
For now, just keep doing as we are always doing. Just point and laugh. But this is a sad, sad commentary of what has become of our nation