Most ideals are unattainable but open society is not. The idea of imperfection or fallibility is an integral part of the concept of open society. It applies with particular force when it comes to intervening in the internal affairs of another country. Most forms of punitive intervention have unintended adverse consequences. Trade sanctions foster smuggling and the smugglers are usually in cahoots with the authorities so that the sanctions actually strengthen the governments whom they are supposed to topple.
Military action tends to silence internal opposition to the regime against which it is directed.
The blacklisting of officials and businessmen associated with a war criminal like Milosevic is relatively more effective. There is something contradictory about imposing democracy from the outside. The contradiction can be avoided only if the intervention brings benefits and is therefore voluntarily accepted. To the greatest possible extent, intervention ought to take the form of incentives and constructive engagement. The idea of fallibility is difficult to accept especially if it applies to oneself.