A fine line exists with this.
For example. The AN-2 is certed to fly here, and does, while not many other AN's (except the -148 maybe) are.
Same with the TU's, I think only the 204 series is certed for here.
IL-68M served the US for many years.
SSJs are, and the MS-21 will be too. These types have an extremely high probability of being picked up by Western airlines, especially the MS-21.
Having said that, no US carrier has operated these planes (or hasn't so far). I personally think if someone in the US wants to operate them, they should have a penalty. The only reason people spam them is because they are cheap, so if you put a penalty on where they cost as much as western types, but guzzle more, I bet people will stop using them.
Russian/Eastern types are used a good amount in other Western Countries however, so that is a totally different story.