A rule that permits consideration of events occurring subsequent to the inception of an instrument that pertains to the vesting of a future interest. If the specified contingency on which the creation of the interest depends actually occurs within the period of the Rule against Perpetuities, the interest is legally enforceable.
Under the Common Law, the Rule Against Perpetuities provides that no interest in property is valid unless it becomes fixed, if at all, not later than twenty-one years, plus the period of gestation, after some life or lives in being at the time of the creation of the interest. The period of gestation is included to cover cases of posthumous birth. A property interest vests when it is given to a person in being, and when the interest is not subject to a condition precedent. The courts developed the Rule Against Perpetuities during the seventeenth century in order to restrict a person's power to control the ownership and possession of his or her property after his or her death, and to ensure the transferability of property.
In order to mitigate the harshness of the Rule Against Perpetuities, some states have embodied the wait-and-see doctrine in statutes. The general concept of wait-and-see is that a perpetuity violation should occur only if an interest actually fails to vest within the perpetuity period. In contrast to the traditional view, which prescribes that the situation is examined as it exists when the interests are created, thereby invalidating the interests if a possibility exists that they will fail to vest in due time, one must wait and see whether, in fact, the possibility turns out to be an actuality.The wait-and-see doctrine is also deemed to be an extension of the Second Look Doctrine.