The guy is not being prosecuted under US law. Why an American national official should be presumed to have the authority to negotiate plea bargains for the International Criminal Tribunal is beyond me.
When the deal was made, Karadzic likely assumed that America was the most powerful country on earth and could get what it asked for from the ICTY. The US asked that the ICTY be set up and the the US asked that it be closed in 2011, and the US got what it wanted in both cases.
No conflict of interest there, huh? Soros exploits the Eastern European Markets and Time Warner sells the juicy details of a grizzly war through its media outlets.
Because ICTY sham was created by the US in clear contravention of UN Charter. It has nothing to do with the international law.
ICTY was created in haste and there is ample evidence of it's illegallity. UN Charter is the top UN document and it describes the powers of each UN body. UN Security Council (UNSEC) does not have legal powers and therefore can not create an auxilliary body with legal powers. All legal power of the UN resides within the World Court, and General Assembly. On top of that, the reason for violation of the UN Charter was to punish alleged Serbian aggression on Bosnia, i.e. the motive for creation was political. That alone puts this sham into the same drawer with Hitler's and Stalin's "courts" and political trials.
The "justice" dispensed in ICTY is neither Continental nor precedent law. It is very likely that any American lawyer having a stint in that circus could be disbarred in his/her local jurisdiction upon returning home. That's why many who served there keep mum of their "success story".