OPINION
STATEMENT OF THE CASE
Petitioner Erna A. Thurston asks this court to review a court of appeals’ opinion reversing summary judgment in her favor. The court of appeals held that Mrs. Thurston is not entitled to have surviving spouse benefits, available under her deceased husband’s pension, calculated according to the statute in effect at her husband’s death. We vacate the court of appeals’ opinion and affirm the trial court’s ruling. We have jurisdiction pursuant to Ariz. Const, art. 6, § 5(3) and A.R.S. § 12-120.24.
FACTS AND PROCEDURAL HISTORY
Mrs. Thurston’s husband, the late C. Edwin Thurston, was a Maricopa County Superior Court judge from January 1, 1965 to February 24, 1976, at which time he applied for and received retirement benefits for medical disability pursuant to A.R.S. § 38-802. When Judge Thurston took office, and when he retired, the statute governing his pension plan provided that his surviving spouse would receive monthly benefits equaling one-third of the monthly benefits being paid to the judge at his death (“one-third benefit”). See A.R.S. § 38-801(0 (1976).
In 1981, after Judge Thurston’s retirement, the legislature amended A.R.S. § 38-801(C), increasing the surviving spouse benefits from one-third to two-thirds of the monthly benefits paid to retired judges (“two-thirds benefit”). In 1985, the legislature essentially repealed the plan under which Judge Thurston retired and merged it into the Elected Officials’ Retirement Plan. This plan, in effect at Judge Thurston’s death, retained the two-thirds benefit. See A.R.S. § 38-807.
After Judge Thurston’s death in December 1989, Mrs. Thurston applied for the two-thirds benefit. The respondent Plan refused Mrs. Thurston’s claim, but agreed to pay her the one-third benefit.
ISSUE
Whether Mrs. Thurston is entitled to surviving spouse benefits in the amount of two-thirds of the monthly benefits her husband was receiving at the time of his death.
DISCUSSION
At the outset, we recognize that the surviv- or benefits can be viewed as both a right of the survivor, vesting upon the death of the employee, and as a contractual right of the employee, vesting at the time the employee begins employment. Regardless of how we view the survivor benefits in this case, whether as a right vesting in Mrs. Thurston or as a contractual right vesting in Judge Thurston, the outcome is the same: Mrs. Thurston is entitled to a two-thirds benefit.
A. Mrs. Thurston’s Right
Viewing the survivor benefits as vesting in the surviving spouse, it is clear that Mrs. Thurston’s right did not vest until her husband’s death. In
Hall v. A.N.R. Freight System, Inc.,
Rights are vested, in contradistinction of being expectant or contingent. They are vested, when the right to enjoyment, present or prospective, has become the property of some particular person or persons a# a present interest____ They are contingent when they are only to come into existence on an event or condition which may not happen or be performed until such other event may prevent their vesting.
(quoting
Steinfeld v. Neilsen,
Having resolved that Mrs. Thurston’s surviving spouse benefits were not yet vested at the time of the 1981 amendment, we must now determine if it was appropriate for the state to alter them. We start by determining whether the right to surviving spouse benefits is substantive or procedural. “ ‘[I]t is generally agreed that a substantive law creates, defines and regulates rights while a procedural one prescribes the method of enforcing such rights or obtaining redress.’”
Hall,
We held in
Hall
that “ ‘substantive rights may not be impaired
1
once vested.’ ” Id.
In this case, because the 1981 amendment occurred before the vesting of Mrs. Thur-ston’s right to survivor benefits, the alteration applies, and Mrs. Thurston is entitled to benefits calculated accordingly.
B. Judge Thurston’s Right
The court of appeals, relying on
Yeazell v. Copins,
Admittedly, some of the Arizona cases dealing with this subject contain some confusing and possibly contradictory language.
Yeazell
holds that “subsequent legislation may not be arbitrarily applied retroactively to impair the contract.”
Yeazell,
At Judge Thurston’s death, his contract provided that his surviving spouse was entitled to benefits equaling two-thirds of his monthly benefits. Because Mrs. Thurston qualifies as Judge Thurston’s surviving spouse, she is entitled to receive those benefits.
DISPOSITION
The trial court correctly granted Mrs. Thurston’s motion for summary judgment. Accordingly, we affirm the judgment of the trial court and vacate the opinion of the court of appeals.
Notes
. We note that the present case involves an improvement. We will use the term "alteration” instead of impairment or improvement.
