Harry is not so clever: why did he think that telling Malfoy "this is a plot, you know it's a plot" would make it not a good idea for Malfoy to commit overkill in defending his son? The point of vengeance is deterrence, and the crack of "well, it might not have been Hermione" is not a good crack to have in your deterrence. Dumbledore even tells Harry as much. And then, to top it off, Harry threatens Malfoy.
What Harry should have done: talked to Malfoy beforehand (why didn't he?). Given that didn't happen, told Malfoy "I have information that is relevant to the attack, which I think you should know but should not be public yet, as it might diminish your capacity for vengeance for this to be known publicly."
Then, in private, Harry has a conversation with Lucius where Lucius doesn't need to play to the crowd, informing Lucius of his expectation of the plot, his respect for Draco, and his vow to punish the murderer of Narcissa, and then Lucius walks back out and asks that the trial be finished in a week.
Even if Harry couldn't get access to Lucius in private, he could have made a much better public proposal.
"Hermione was not your family's true enemy, as you and I both know. To you, she is nothing but a pawn symbolizing the foe you can't yet strike. But she has value to me. If you want the right to deliver her to Azkaban, so be it, but hold off on claiming that right, Lucius, and I will give you your real enemy. You can spend your anger on this one little child now. But then I will owe you nothing, and your enemy will laugh at you. Or take today's judg...
EDIT: New discussion thread here.
This is a new thread to discuss Eliezer Yudkowsky's Harry Potter and the Methods of Rationality and anything related to it. With two chapters recently the previous thread has very quickly reached 500 comments. The latest chapter as of 17th March 2012 is Ch. 79.
There is now a site dedicated to the story at hpmor.com, which is now the place to go to find the authors notes and all sorts of other goodies. AdeleneDawner has kept an archive of Author's Notes. (This goes up to the notes for chapter 76, and is now not updating. The authors notes from chapter 77 onwards are on hpmor.com.)
The first 5 discussion threads are on the main page under the harry_potter tag. Threads 6 and on (including this one) are in the discussion section using its separate tag system. Also: one, two, three, four, five, six, seven, eight, nine, ten.
As a reminder, it's often useful to start your comment by indicating which chapter you are commenting on.
Spoiler Warning: this thread is full of spoilers. With few exceptions, spoilers for MOR and canon are fair game to post, without warning or rot13. More specifically: