If my sister killed a friend of mine that I didn't want to kill, in fact was pretty deliberately protecting, you can bet it's going to be an issue between us for a couple of months.

As betrayals go, that's pretty high up on my list of possibles. She's free to hit the foxhole with any of my exes she wants, but don't kill the guy I had a crush on in high school, please?

If my sister killed a friend of mine that I didn't want to kill, in fact was pretty deliberately protecting, you can bet it's going to be an issue between us for a couple of months.

I think it was compounded by Sam feeling like Dean was being the all-knowing older brother again, and not trusting Sam to make the right decision. And Sammy don't like that.

I did think that Dean's motivation for killing her was really weak -- he didn't even work the case. And there's precedent for not killing, going back to Lenore. So in the end, I think it was a storyline that got shoehorned in to provide some brotherly conflict in a season where there wasn't much.

I saw it in character for Dean. He's hypocritical about this shit (cf making deals with Crowley), and she was killing people. I at least figured he'd done that much due diligence--partially because he was right. Lenore had "I'm not doing it now" to add to her "I won't do it ever". Amy had clearly gone against her word for something more important.

Also, perhaps Dean understands he will kill people at the drop of a hat for Sam, so why wouldn't she do that for her charge?

(I did mention the hypocrite thing, right?)

Also true. Oh, DEAN.

This conversation is weird, though, because every time I see "Amy," I think, What did I do?!

YOU KILLED PEOPLE.

(that never happens to me. I just sit around, mooning...)

Well, I usually try not to ...

It's not your fault, Amy. It's just your nature.

That's what they tell me ...

Wow, hiatus feels long already.

I wonder if Sam is consciously aware that his stance on monsters has changed - he seemed to accept that Madison had to die, despite the fact that she wasn't deliberately killing people. And I'd think her own acceptance of that necessity would argue more compellingly for her resolve to avoid killing people than Amy pleading for her life and pinkie swearing that she'd never murder anyone for their brains again (unless her kid got another case of the sniffles, of course).

I'd think her own acceptance of that necessity would argue more compellingly for her resolve to avoid killing people

But her resolve had just been pointed out to be useless. Amy had been seen to act in direct conflict with her nature, by killing her own mother to save Sam's life. All the good thoughts on Madison's side were clearly irrelevant and she was going to kill the next time she had an opportunity.