cosmoline said:
The OSS guys trained to use them as a backup because they weren't always going to be able to have rifles or handguns. And of course they also essentially trained to kill people with them in circumstances that had nothing to do with self defense.
I think that is an important distinction.
Knives are highly effective if the target does not see it coming, or if the target is not well armed and the attacker knows what they are doing with the knife. A knife against an unnarmed person or person with thier armament holstered or slung can be highly effective. This is most of the use OSS and CIA type covert agents would have for such things. Killing the guy not expecting to suddenly be attacked with a knife.
Certainly they would train to actually fight with it too, but actually fighting would be avoided in favor of killing the unsuspecting.
However such circumstances have very little to do with lawful self defense.
In most circumstances that will actually justify legal lethal force the assailant is armed with a lethal weapon. It is this lethal weapon that typically makes them a lethal threat and makes use of lethal force against them lawful.
That is a game changer, because you are no longer talking about how to disable or injure someone with a knife that is just attacking you, but someone that will be using thier own weapon at the same time.
They also are likely initiating the violence, and so are already aware of the impending fight, removing some of the element of surprise and making overwhelming and devastating use of the knife more difficult for the defender.
I am aware of many of the knife fighting techniques, and they can look quite impressive demonstrated by someone in a controlled setting.
However it is very likely both will get cut in a real fight if the attacker has already committed to attack, even if one does more effective damage.
Furthermore the fact that you are on more equal footing, and if the opponent regains control can turn the tides and kill you means keeping the momentum of success is far more important in a knife fight. If you give a good attack and then stop and they get back into the fight you may still lose even though the option to control the outcome had been held by you. If you continue the attack after they are temporarily stopped it may be seen as excessive force to continue, as the threat is momentarily stopped.
Judged by jury members, investigators, etc after the fact used to applying firearm defense logic many of the acts that may be required in using a knife and prevailing may seem more excessive.
With a gun you stop the threat, and then have the luxury of standing at the ready with a ranged weapon with a clear advantage over the downed individual and can refrain from using additional force unless needed without much additional risk to yourself. Then if they choose to get back into the fight you can shoot again if necessary before they have much chance of turning the tides on you.
That is not true if you are holding a knife and you give them the luxury of deciding they want to try again. How disabled they are is much more important when fighting with a knife.
The level of force required may be well in excess of the simple shot required from a firearm, and the extensiveness of the knife wounds even less survivable and seen as more excessive. Imagine being in court and hearing a dozen stab wounds slowly counted by a prosecutor pausing a second between each one. It would sound excessive even if they were all delivered rapidly during a grapple.
You as a result are far more likely to end up in prison if you defend yourself with a knife than with a gun.
Additionally use of a knife seems more gruesome. The housewife on the jury may relate to pulling a trigger against something she is scared of posing a lethal threat, but probably won't relate to systematically taking apart a person with a knife. This may mean guilty instead of not guilty.
It can still be a valuable skill. I myself sometimes carry a knife for defense. However it is a far from ideal tool. Both in use and in the likely aftermath.