Good thing there is that whole court system and associated bureaucracy rather than autocratic rule supporting "accuse them of being evil for any reason". If any "investors" are actually wondering whether they're at significant risk of the US government "refusing to pay them" (read: seizing their assets), their first stop should be an attorney who can give them a rough idea if they're engaged in illegal activity. This is a good idea if one has any assets within the reach of US jurisdiction, regardless of whether those assets are government bonds or not. And sure the justice system, the legal system, and USian pan-jurisdiction all have their problems. But with this situation of ethnic cleansing in service of some hollow Make Russia Great Again nonsense, both the legal outcome and the morality are quite clear cut.