well .su is Russia. Not sure how to say this without pissing a lot of people off but it would not surprise me if there were some treaties they signed to cooperate with US LE in the not-so-distant future based on how things are going. Also they can seize the domain for themselves.
the .to domain I believe can be seized but I don't know the conditions. .is can be seized but it is rare. The other thing is that treaties can be changed and the US can strong-arm people. Right now they work, I don't know if they always will.