On the other hand, she did seem willing to give a full confession and whatnot (at least after a bit of roughing up), which may count towards leniency. Had she stayed mum, it doesn't appear as if anybody would have any real evidence of, well, anything much.
One assassin is dead, his connection to either the Klingons or his Starfleet colleagues unestablished and his attempt to distance himself from both evident from his use of a disguise... Two other assassins are dead as well, the related computer logs apparently all wiped. General Chang has been blown to smithereens, in a ship whose very existence would no doubt be denied by most. And even after Valeris implicated Ambassador Nanclus, it sounds quite unlikely either the Feds or the Klingons could do anything to prosecute him!