[sic] or otherwise alienated from the purposes herein expressed and intended.' . . . The property was to go to Benton County (County) or the State of Washington (State) if this direction was violated.  That provision violates the rule against perpetuities and is therefore void.  The question before us is whether the interest that remains is fee simple absolute (as the Hospital maintains) or whether, instead, it is fee simple determinable (in which case the Diocese of Olympia, Inc. . . . would have an interest under the will of one of Mr. Luth's beneficiaries).  We conclude that the resulting interest is fee simple absolute in the Hospital . . . .”

The rule against perpetuities is a rule of law in most states that is derived from English law of the same name.  Washington's rule against perpetuties is typical of the rule and it is:

The rule against perpetuities requires that future estates vest or fail within “a life or lives in being at the time of the testator's death and twenty-one years thereafter.”

The purpose of the rule is to prevent the control of real property from the grave.  See the Court's opinion.

For more on the rule, watch one of my all-time favorite movies “Body Heat” with Kathleen Turner and William Hurt.  Rottentomatoes.com compiles ratings of critics and 97% of them like this movie.

During one hot and sultry Florida summer, a shady lawyer launches into a torrid relationship with a lonely woman married to a rich businessman. As their relationship grows, she decides to enlist his help in killing her husband so that the two can live comfortably off his riches. After they've successfully completed the deed, the lovers' relationship sours, and they both become principal suspects in the police investigation.

Arizona's rule against perpetuities is found in Arizona Revised Statutes Section 14-2901.A that states:

A nonvested property interest is invalid unless at least one of the following is true:

1. At the time the interest is created it is certain to vest or to terminate not later than twenty-one years after the death of a person who is then alive.

2. The interest either vests or terminates within five hundred years after its creation.

3. The interest is under a trust whose trustee has the expressed or implied power to sell the trust assets and at one or more times after the creation of the interest one or more persons who are living when the trust is created have an unlimited power to terminate the interest.