As soon as I saw that David Warner was in the cast, I knew that there would be great acting based on a profound script in these episodes (parts I & II). Not that Warner did all of the good acting exuding malevolent gravitas with a touch of ironic and perverse bonhomie; it just seemed that his presence inspired the others to even better acting. Stewart as Picard was at his Shakespearean best. There was also the redoubtable Ronny Cox, whose acting talent has allowed us to suspend disbelief in so many movies. His portrayal of a harsh, by-the-book, unfeeling officer in command undoubtedly made audiences hate him at first. That is, until the end when his actions revealed that he cared for the welfare of Captain Picard after all.
Although broadcast in 1992, I couldn't help but be struck by the immediate currency today (2011) of the moral, legal and psychological issues put forth in the story - torture sanctioned by government, the reliability of information obtained under torture, the psychology of the torturer and the tortured.
In relating his experience under torture to Counselor Troi, Picard brought to light one of the effects of torture that had been in the peripheral vision of my mind but had never articulated: It is often said that the tortured would confess or reveal anything his handlers would like to hear just to stop his torment. But Picard shows that the victim himself would get to believe the lie that he is forced to confess. In other words, he would not be lying but telling the truth as he believes it as a form of psychological defense. In essence, therefore, brainwashing is a consequence of torture. And that is exactly, how some misguided authorities use it - to brainwash.
So in the story, it became obvious, that the purpose of David Warner's character was not to get any kind of truth from Picard, but to brainwash him to get him to confess to some kind of Federation transgression of its treaty with the Cardassian Empire. In that way, the Cardassians may be able to intimidate the Federation into ceding territory to them.
For more about brainwashing in movies, see John Frankenheimer's The Manchurian Candidate (1962) with Laurence Harvey in the anti-hero role and also the Ipcress File.