Sticking knives into people is wrong.
It's always wrong.
There's never a case where cutting people with knives is or other blades is wholly right, moral, ethical or proper.
It always is accompanied by physical damage to the victim, damage which may never heal, and which historically has caused untold pain and suffering, be it via dagger, sword, guillotine or scalpel.
But... it can be the lesser of two evils.
Society accords a respected place to people who actually make their living out of carving people up, sometimes removing whole organs. We call them "surgeons".
We also have places for people who carve up others for fun, we call them "mass murderers" and shun them.
So the next time someone says "War is never justified", and that "Saddam could have been contained indefinitely", think about the role of Surgery in Medicine. Whether the diseased organ was infectious or not is still subject to controversy: but that the surgery relieved untold suffering is only deniable by the terminally reality-challenged. And by the doctors who were making a nice living out of the drugs they were giving the patient that actually increased the damage, the "Oil for Palaces" programme so dear to the hearts of Chirac and Putin.