Harry Potter and the Methods of Rationality

"You ransom Aberforth, you lose the war," the man said sharply. "That simple. One hundred thousand Galleons is nearly all we've got in the war-chest, and if you use it like this, it won't be refilled. What'll you do, try to convince the Potters to empty their vault like the Longbottoms already did? Voldie's just going to kidnap someone else and make another demand. Alice, Minerva, anyone you care about, they'll all be targets if you pay off the Death Eaters. That's not the lesson you should be trying to teach them."

"If I do this I will have no one. No one." Dumbledore's voice broke, the world tilted as the outlooking head fell down into the ancient hands, and awful sounds came from not-Harry's throat as he began to sob like a child.

"Shall I tell Voldie's messenger no?" said Alastor's voice, now strangely gentle. "You don't have to do it yourself, old friend."

"No - I will say it myself - I must -"

The memory ended with a shock and Harry ripped his head out of the glowing water, gasping as though he'd been deprived of air.

The transition between scenes, between decade-old reality and present moment, was another jolt to Harry's mind; in some fashion his immersion in the past had unanchored him. The broken old man sobbing in his office had been another person in another era, Harry had understood that much; someone softer -

Before it had all vanished like dissipating smoke, returning the now, the present day.

Terrible and stern stood the ancient wizard, like he was carven from stone; beard woven of thread like iron, half-moon glasses like mirrors, and the pupils behind as sharp and unyielding as black diamond.

"Do you also wish to see my brother as he died under the Cruciatus?" said Albus Dumbledore. "Voldemort sent me that memory as well!"

"And that - " Harry was having trouble producing a voice, for the growing sickness in his chest. "That was when -" The words seemed to burn in his throat, as the awful knowledge dawned on him, the horrible understanding. "That was when you burned Narcissa Malfoy alive in her own bedroom."

Albus Dumbledore's gaze was cold as he answered. "To that question only a fool would say yea or nay. What matters is that the Death Eaters believe I killed her, and that belief kept safe the families of all who served the Order of the Phoenix - until this day. Now do you understand what you have done? What you have done to your friends, Harry Potter, and to any that stand with you?" The old wizard seemed to grow still taller and more terrible, as his voice rose louder. "You have made them all targets, and targets they will remain! Until you prove, the only way it can be proven, that you are no longer willing to pay such prices!"

"And is it true?" Harry said. There was a buzzing sensation filling him, his body growing more distant. "What Draco said, that Narcissa Malfoy never got her hands dirty, that she was only Lucius's wife? She was an enabler, I get that, but I can't back that deserving being burned alive."

"Nothing less would have convinced them that I was done with hesitation." The old wizard's voice brooked no question and no refusal. "Always I was too reluctant to do as I must, always it was others who paid the cost of my mercy. So Alastor told me from the beginning, but I did not listen to him. You, I expect, shall prove better at such decisions than I."

"I'm surprised," Harry said, amazed that his voice was almost steady. "I would have expected the Death Eaters to go after another Light family and start a cycle of escalating retaliation, if you didn't get them all with your first strike."