Model Penal Code sec. 3.02

(1) Conduct that the actor believes to be necessary to avoid a harm or evil to himself or to another is justifiable, provided that:

(a) the harm or evil sought to be avoided bysuch conduct is greater than that sought to be prevented bythe law defining the offense charged; and

(b) neither the Code nor other law defining the offense provides exceptions or defenses dealing with the specific situation involved; and

(c) a legislative purpose to exclude the justification claimed does not otherwise plainly appear.

(2) When the actor was reckless or negligent in bringing about the situation requiring a choice of harms or evils or in appraising the necessity for his conduct, the justification afforded bythis [43] Section is unavailable in a prosecution for any offense for which recklessness or negligence, as the case may be, suffices to establish culpability.

Subsection (1) states a general principle of choice of evils, with limitations on its availability designed to confine its use to appropriate cases. The evil sought to be avoided must be greater than that sought to be prevented bythe law defining the offense. The legislature must not have previously foreclosed the choice that was made byresolving the conflict of values at stake.

Subsection (2) applies in this context the general provision of Section 3.09(2).As provided in Subsection (1),the actor's belief in the necessity of his conduct to avoid the contemplated harm is a sufficient basis for his assertion of the defense. Under Subsection (2), however, if the defendant was reckless or negligent in appraising the necessity for his conduct, the justification provided bythis section is unavailable in a prosecution for an offense for which recklessness or negligence, as the case may be, suffices to establish culpability. The same provision is made for cases in which the defendant recklessly or negligently brings about the situation requiring the choice of evils.

For detailed Comment, see MPCPart I Commentaries, vol. 2, at 9.