The United States has maintained a visa blacklist for Transdniestria, which the European Union joined in 2003. There are only two places in Europe whose leaders are banned from traveling abroad: Belarus and Transdniestria.
In both cases, the visa bans are politically motivated. Both countries have political systems that the United States wants to isolate and then change.
Neither of these two countries are a threat to their neighbors or the rest of the world.
The United States, whose leaders have launched wars and invasions consistently throughout the years, and are guilty of some of the worst human rights violations in the world today, are not on any Visa Ban blacklist.