[supercat]

He used cruciatus on Carrow when Carrow spat in McGonigall’s face.

He also used the Imperius Curse at Gringotts.

Since there's no talk about any sort of bad consequences for either of them, Rowling actually makes a pretty strong statement about what must be done in time of war.

Using Unforgiveable Curses on Death Eaters might be justified, but I don't see the justification for using an Unforgiveable Curse at Gringotts. I'm pretty certain the Imperius Curse is unforgiveable, isn't it?

[Obi-Wandreas]

In Goblet of Fire, the fake Moody points out that the use of any of these curses on "another human being" is unforgivable. Goblins, it appears, do not have any more protection under wizard law than centaurs or house elves; though they are all sentient beings, they are considered just barely above animals.

[Dianna]

Using Unforgiveable Curses on Death Eaters might be justified, but I don't see the justification for using an Unforgiveable Curse at Gringotts. I'm pretty certain the Imperius Curse is unforgiveable, isn't it?

Yes, Imperius is an unforgiveable curse, but do you see any other way for them to get the horcrux from the vault?

I'm not typically one for "ends justify the means", but when you're talking about Voldemort taking over and all the deaths...so, Harry made a goblin open some doors and another guy go and hide himself. It doesn't seem THAT bad to me.