What is the necessity defense exactly and how and under what circumstances might it work? Say there is a fire in a maximum security prison, and the prisoners, threatened by death, break out of their cells. Surely they are not guilty of the crime of escape? Here's a situation where most of us would agree that necessity could be a defense and that the prisoners who broke out of their cells "out of necessity" ought not to be convicted for escape. And what do you make of the following cases:

The Model Penal Code, from which many states draw the language they use in wording their statutes, defines the necessity defense as follows:

"Conduct that the actor believes to be necessary to avoid harm or evil to himself or to another is justifiable, provided that: . . . the harm or evil sought to be avoided by such conduct is greater than that sought to be prevented by the law defining the offense charged."

The Code appears to give defendants a fairly wide latitude. Which of the five cases above would you defend on grounds of necessity? Then consider the following:

Would you defend John on grounds of necessity? Why? If not, why not? In its general form, as stated in the Model Penal Code, the principle appears to involve the making of some sort of a calculation. "Harm to be avoided" has to be calculated and added up and then set against the "[harm] sought to be prevented by the law defining the offense charged." The principle itself, however, gives little guidance as to how the balance is to be struck or for that matter much guidance as to what weights to assign in the first place. John's trolley dilemma would appear to be fairly uncomplicated in this regard. It would appear to involve the weighing of the loss of five lives against the loss of just one. Is this the choice, are these the alternatives? It would appear that the loss of five lives is worse (would be worse) than the loss of only one life.

But is this the best way to couch the choice? Isn't there another difference between the two alternatives, a difference that might make a difference, that is not captured by describing the alternatives as a chocie between the number of lives lost? If John chooses, for instance, the latter alternative over the former, he actually kills another human being, whereas if he does not turn the trolley he is letting five die. There may be only a small difference in this situation between killing and letting die, but generally we take it to be a difference that makes some moral difference. Does the moral difference between killing and letting die prompt you to give different weights to the alternatives John faces, to assign, for instance, a greater weight to the harm John would cause by turning the trolley onto the right hand track? Does the moral difference in this case between killing and letting die make enough of a difference to effect how, in applying the necessity principle, the balance of relative harms would be (ought to be) struck? The moral difference between killing and letting die would appear to make just this sort of a difference in the following (hypothetical) case:

If you were John's attorney, would you argue his case on grounds of necessity? Why not? Wouldn't Cardozo's "No Rule of Human Jettison" apply equally well here? And if John had refused the Captain's offer, would he have been subsequently accused of any crime? What crime would that have been? What do our laws presently encourage someone in John's position to do? If John refused the Captain's offer, would you find him guilty of causing the deaths of all ten villagers? Why not?

Perhaps John should not have gone on this botanical expedition after all; perhaps he should have stayed home with Alice or gone on that cruise with her to the Bahamas. Then, at least, he would not be in such a pickle. Some other pickle perhaps, but, at least, not this pickle. What's the difference between the two situations in which John finds himself as a trolley driver and now as a botanist? Why is necessity more likely to succeed as a defense in the former case than in the latter? Or perhaps it ain't so. What do you think? Before making up your mind, you may wish to discuss this case with your fellow Justices and to see if you can reach any kind of a consensus.

The necessity defense clearly involves more than just "doing the numbers," that is, involves more than just adding up good and bad consequences and calculating whether the result comes out on the plus or minus side. This can be neatly demonstrated by the following hypothetical case:

Would you defend John on grounds of necessity? Why not? Why does this case fail to meet the test of the Model Penal Code?

One question to ask, right off the bat, is (surely) was what the defendants did really necessary. Most states (in our country), however, merely require of a defendant who pleads necessity that he have a reasonable belief that he is in a situation of necessity. Take the following case, for an instance:

Most states would acquit John on the grounds that he reasonably believed that Alice was injured. What about the following cases?

John, who always fancied himself as a bit of a playboy, borrows Alice's Jaguar for a joy-ride around town. While speeding down Main street, tape deck blaring, the brakes fail and he loses control of the car. The car is heading straight for an intersection where a group of 20 nursery school children are crossing with their teachers. He could let the car continue on its path or swerve into the bookshop on the corner where there is a salesperson in the window changing the window display. If he smashes into the group, he may only be charged with involuntary manslaughter. If he plows into the bookshop, he could be charged with voluntary manslaughter, perhaps even murder. John decides to run the Jaguar into the bookshop. He turns the wheel and crashes into the window display, killing the salesperson instantly. He is arrested and charged with voluntary manslaughter. He pleads necessity. If he had not crashed into the bookshop, he argues, many more people would have died. If you were the judge, would you find John guilty as charged?

It is tempting to think that John and Alice in the first case and John in the second case have courted their own disaster and so should not be allowed to invoke necxessity as a defense. Shouldn't a defendant be completely blameless in order to be able to defend himself on grounds of necessity? What would happen in the above cases? Despite our feelings about the blameworthiness of the defendants, John and Alice are not likely to be convicted of misappropriating Henry's goods since reckless acts of misappropriation are not crimes, only intentional acts are. They are likely to be acquitted. In the other case, John is ikely to be acquitted of murder or manslaughter for driving into the storefront window on grounds of necessity, but he would in all liklihood be convicted of manslaughter for driving recklessly in the first place, since his recklessness eventually resulted in someone's death.