OPINION
FABE, Justice.
Brian Ross has been absent from the State of Alaska since 1990, first as a student at the
Ross now appeals to this court, arguing that the ten-year rule violates his equal protection and substantive due process rights. But because the ten-year rule and congressional exception are fairly and substantially related to the legitimate state interests of limiting dividends to permanent Alaska residents and preventing fraud, and because the ten-year rule is rationally related to the legitimate state purpose of reducing administrative burdens, we affirm the superior court as to these claims. Ross also argues that the ten-year rule is unconstitutionally retroactive. But because the rule does not give his pre-enactment conduct a different legal ef-feet, we affirm the superior court on this point as well.
II. FACTS AND PROCEEDINGS
Brian Ross was born and raised in Alaska. In 1990 he left the state to attend the United States Naval Academy. Following his graduation from the Naval Academy, Ross pursued a career in the Marine Corps that has prevented him from living in the State of Alaska for the past 18 years. Despite his absence, Ross has maintained his Alaska residency.
Alaska Statute 48.23.008 provides that absent individuals may still remain eligible for the dividend if their absences are for secondary education or active duty in the military, among other reasons. Accordingly, Ross received a permanent fund dividend every year since the first one was issued in 1982. Starting in 1996, after he had been absent five years, Ross was required to provide documentation every year demonstrating to the Department of Revenue's satisfaction that at all times during his absence he had intended to return to Alaska to remain permanently. From 1996 to 2008, he did this every year, detailing his nearly annual visits to Alaska, his ownership of real property in Alaska, his maintenance of Alaska residency, his titling of vehicles in Alaska, his consistent voting in Alaska elections, his purchase of resident hunting and fishing licenses, and his familial ties to Alaska.
In 1998 the Alaska Legislature amended AS 48.28.008 to provide that "[an otherwise eligible individual who has been eligible for the immediately preceding 10 dividends despite being absent from the state for more than 180 days in each of the related 10 qualifying years is only eligible for the current year dividend if the individual was absent 180 days or less during the qualifying year."
Because of the rule, the State denied Ross a dividend for the first time in 2009. Because Ross was not eligible to receive a dividend, his three minor children were also denied dividends.
III. STANDARD OF REVIEW
When the superior court sits as an intermediate appellate court reviewing an agency decision, we "do not defer to the superior court's decision."
IV. DISCUSSION
On appeal, Ross raises essentially the same four arguments that he did in his appeal before the superior court. He also adds a fifth argument that the superior court erred by relying on an unpublished memorandum opinion of this court and that its ruling should therefore be reversed. Because none of Ross's arguments merit reversal, we affirm the superior court decision upholding the Department of Revenue's denial of dividends to Ross and his children.
A. The Ten-Year Rule Does Not Violate Equal Protection.
Ross first argues that AS 43.23.008(c) violates the equal protection clauses of the Alaska and federal constitutions for two reasons: First, it unconstitutionally distinguishes between residents absent for ten years and those absent for fewer (or not at all); and second, because it unconstitutionally distinguishes between members of Congress (and their staffs) and those who are absent for other reasons.
1. Equal protection standards of review
We have heard state equal protection challenges to permanent fund dividend eligibility requirements several times before. Most recently, in Harrod v. State, Department of Revenue, we set out the analytical basis for our decisions in this area:
We have adopted a flexible "sliding scale" test for reviewing equal protection claims. First, we determine what weight should be afforded the constitutional interest impaired by the challenged enactment. The nature of this interest is the mostimportant variable in fixing the appropriate level of review. Second, we examine the purposes served by a challenged statute. Depending on the level of review determined, the state may be required to show only that its objectives were legitimate, at the low end of the continuum, or, at the high end of the scale, that the legislation was motivated by a compelling state interest. Third, an evaluation of the state's interest in the particular means employed to further its goals must be undertaken. -
We have previously held that PFDs are not basic necessities or a fundamental right. Instead, a PFD is merely an economic interest and therefore is entitled only to minimum protection under our equal protection analysis. Restrictions on economic interests are reviewed at the low end of the sliding scale. Our review is therefore limited to considering whether this regulation was designed to achieve a legitimate governmental objective and whether it bears a fair and substantial relationship to accomplishing that objective. At this level of review, we do not determine whether a regulation is perfectly fair to every individual to whom it is applied.[7 ]
We have similarly applied the lowest level of serutiny when reviewing equal protection challenges to dividend eligibility requirements under the federal constitution. In State, Department of Revenue, Permanent Fund Dividend Division v. Costo, we emphasized that "a dividend is a matter of grace, a governmental 'benefit' indistinguishable from other forms of social welfare, which the [U.S. Supreme] Court suggested merits mere rational basis review. Thus, the State's dividend eligibility requirement only warrants rational basis review."
2. The ten-year rule does not unconstitutionally distinguish between Alaska residents absent for ten years and Alaska residents absent for fewer than ten years.
Ross argues that the ten-year rule violates the federal Equal Protection Clause because it serves none of the State's three explicit purposes in enacting the permanent fund dividend, as described by the United States Supreme Court in Zobel v. Williams:
(1) to provide a mechanism for equitable distribution to the people of Alaska of at least a portion of the state's energy wealth derived from the development and production of the natural resources belonging to them as Alaskans; (2) to encourage persons to maintain their residence in Alaska and to reduce population turnover in the state; and (8) to encourage increased awareness and involvement by the residents of the state in the management and expenditure of the Alaska permanent fund.[10 ]
Ross does not argue that the ten-year rule violates the Equal Protection Clause of the Alaska Constitution.
As the State points out, "minimal serutiny under the Alaska Constitution is more demanding than rational basis review under the U.S. Constitution"; thus, if the rule does not violate Alaska's Equal Protection Clause, it does not violate the federal Equal Protection Clause.
Ross argues that the United States Supreme Court in Zobel identified the legitimate state interests for any classification relating to the dividend: (1) equitably distributing the State's energy wealth to the people of Alaska, (2) encouraging people to maintain residence in Alaska, and (8) encouraging awareness and involvement by residents in the fund's management.
The State proffers three justifications for the ten-year rule. The first two, PFDs to permanent Alaska residents and preventing fraud in the distribution of PFDs," are, the State argues, "legitimate governmental objectives given that the purposes of the PFD program are to equitably distribute a portion of the state's mineral wealth to Alaskans, to encourage people to stay in Alaska, and to increase citizen involvement in the management of the permanent fund." The State relies on Church v. State, Department of Revenue for this argument.
This case presents a slightly different question than Church, because here Ross has been denied a dividend based not on the purpose of his absence, but rather on the duration of his absence. Nonetheless, here, as in Church, cutting off discretionary review of applications after a ten-year absence is a way of limiting the dividend to permanent
was no doubt intended to prevent an individual who might move to the State of Alaska, establish residency to qualify for a dividend, and then at some point, leave the state with no intention of returning, and yet still attempt to collect a dividend while in the Lower 48. The vast majority of U.S. servicemen and women who get stationed in Alaska as members of the U.S. Army and Air Foree probably fit into this category. The typical individual gets stationed in the State for a 38-year tour during which they establish residency, collect a dividend for a few years, and then get military orders to another base or station. He or she rarely or never returns to the State, probably establishes residency somewhere else at some point, and yet still attempts to collect their precious PFD windfall. While the individual might make it past the 5-year absence rules and regulations, the ten year timeframe as per the statutes is surely made to be the ultimate disqualifier.
Ross's argument illustrates that a rational person could conclude that the ten-year rule furthered the State's interest in preventing fraud and limiting the dividend to bona fide Alaska residents. Even if application of the rule may seem harsh in the case of a lifelong Alaskan Marine who, the superior court noted, "strongly demonstrates [his] passion for retaining residency in Alaska," as we have observed in past cases, when reviewing dividend eligibility requirements under the Alaska Equal Protection Clause, "we do not determine whether a regulation 'is perfectly fair to every individual to whom it is applied'"
The State also proffers a third justification for the law, arguing that "the ten-year rule helps ease the burden on [Department of Revenue] staff of determining residency and eligibility for each of the more than 600,000 people who apply for a PFD each year." As the State points out, we have previously noted that the State has a legitimate interest in creating rules that ease the administrative burden of processing dividend applications."
But in this case, as in Church, by eliminating the need for discretionary review of dividend applications for those who have been out of the state for ten straight years, the ten-year rule functions as an "efficient way to limit PFD eligibility to permanent residents."
3. The congressional exemption to the ten-year rule does not violate equal protection.
The ten-year rule applies to all otherwise exceusably absent residents except for those "serving as a member of the United States Congress," "serving on the staff of a member from this state of the United States Congress," and accompanying, as a spouse or a dependent, a member of Congress or congressional staffer.
The State argues that "the exception recognizes that prolonged absences by members of Congress and their staff are distinct from (ie., not similarly situated to) other allowable absences," because "members of Congress and their staff must spend much of their time in the nation's capital" while "maintain{ing] significant ties to Alaska." The State argues that the legislature could reasonably conclude that the "unique nature" of absences for members of Congress and their staffs "is consistent with an intent to return to Alaska." Here the legislature apparently concluded that the ties that bind a member of Congress or a congressional staffer to Alaska are strong enough to indicate an intention to return to Alaska indefinitely to reside, thus vitiating concerns of fraud and dividends being paid to non-Alaskans. Just as in Harrod the status of serving as a member of Congress or congressional staffer served as a proxy for proving subjective intent to remain, so the congressional exception bears a fair and substantial relationship to the goals of limiting the dividend to permanent Alaska residents and preventing dividend fraud.
B. The Ten-Year Rule Does Not Deny Ross Substantive Due Process.
Ross next argues that the ten-year rule denies him substantive due process because it "denie[d] a PFD to a lifelong Alaskan Marine, while providing an exception for the Congressman who sent him to war, shock[ing] the universal sense of justice." Although he notes that in Church v. State, Department of Revenue, we held that "dividend eligibility requirements do not reach the level of unfairness necessary to support a due process violation" but "are a reasonable way to ensure that only legitimate permanent residents receive PFDs,"
In Church, we noted that "(tlhe standard for establishing a substantive due process violation is rigorous. A due process claim will only stand if the state's actions 'are so irrational or arbitrary, or so lacking in fairness, as to shock the universal sense of justice'"
Ross next argues that the ten-year rule is "illegal[ ] retrospective legislation because it gives [Ross's] pre-enactment conduct [of choosing to pursue a career in the Marine Corps] a different legal effect from that which it would have had without the passage of the statute." Ross contends that he could not now comply with the ten-year rule unless he were to go AWOL or to resign from the Marine Corps.
The State responds that the ten-year rule is not retroactive because it "affects whether [Ross's] absence in calendar year 2008 is allowable for purposes of qualifying for a 2009 PFD," and not "whether [Ross's] pre-enactment absences were allowable."
In Pfeifer v. State, Department of Health & Social Services, Division of Public Assistance, we described the meaning of retroac-tivity:
A statute will be considered retroactive insofar as it gives to pre-enactment conduct a different legal effect from that which it would have had without passage of the statute. A statute creates this different legal effect if it would impair rights a party had when he acted, increase a party's liability for past conduct, or impose new duties with respect to transactions already completed.[29 ]
The ten-year rule is not retroactive because it did not change the legal effect of Ross's eight years of absences occurring before the rule's enactment. It only affects whether his absence in 2008 was allowable, and only considers the absences for the ten years following the rule's enactment. The ten-year rule was enacted in 1999
D. The State Is Not Estopped From Denying Ross A Permanent Fund Dividend.
Ross also argues that the State is estopped from denying him a dividend after it "asserted" eligibility requirements in 1990 on which he "reasonably relied" in choosing a military career.
Although the parties address the elements of equitable estoppel, promissory estoppel is the appropriate doctrine to be analyzed in this case. In Simpson v. Murkowski, we heard a claim, brought as an action in equitable estoppel, against Governor Frank Mur-kowski's elimination of longevity bonuses for seniors.
the primary difference between promissory and equitable estoppels is that the former is offensive, and can be used for affirmative enforcement of a promise, whereas the latter is defensive, and can be used only for preventing the opposing party from raising a particular claim or defense. Because Simpson seeks to enforce an alleged promise, the four-part test for promissory estoppel set forth by this court in Zeman [v. Lufthansa German Airlines,699 P.2d 1274 (Alaska 1985)] is the appropriate test.[32 ]
In this case, Ross is seeking to enforce an alleged promise-namely the State's supposed promise to pay him a dividend-and not to prevent the State from raising a defense to paying a dividend. Therefore, the promissory estoppel analysis controls this case.
In order to prove promissory estop-pel, Ross must establish:
(1) The action induced amounts to a substantial change of position;
(2) it was either actually foreseen or reasonably foreseeable by the promisor;
(3) an actual promise was made and itself induced the action or forbearance in reliance thereon; and
(4) enforcement is necessary in the interest of justice.[33 ]
"To make out a claim for promissory estoppel, one must show that 'an actual promise was made.'"
E. The Superior Court's Citation Of An Unpublished Memorandum Opinion Was Not Reversible Error.
Ross finally argues that the superior court's decision ought to be reversed because that court erroneously relied on an unpublished memorandum opinion of this court. But because we review the superior court's ruling using our independent judgment,
F. Because Ross Is Not Eligible To Receive A Dividend, His Children Are Not Eligible.
Under 15 AAC 28.113(b),
[a] child who otherwise qualifies is eligible to receive a dividend if the child is ... in the lawful and physical custody of a sponsor who is eligible for a dividend, would have been eligible for a dividend had the sponsor filed timely, was only ineligible due to AS 48.23.005(d) [ineligibility due to conviction - or incarceration], or forfeited dividends under AS 48.28.085(a) or (c) [ineligibility due to fraud or aiding an ineligible collection of a dividend].
Because Ross is not eligible for a dividend, his sponsored children are not eligible for dividends.
v. CONCLUSION
As the administrative law judge in Ross's agency appeal noted, "Ross raises questions about the means selected by the legislature to determine who should remain eligible to receive a PFD." And as we have observed in the past, "[it is not a court's role to decide whether a particular statute or ordinance is a wise one; the choice between competing notions of public policy is to be made by elected representatives of the people."
Notes
. AS 43.23.008(c).
. See 15 Alaska Administrative Code (AAC) 23.113(b)(1) and (e) (2012):
(b) A child who otherwise qualifies is eligible to receive a dividend if the child is
(1) in the lawful and physical custody of a sponsor who is eligible for a dividend, would have been eligible for a dividend had the sponsor filed timely, was only ineligible due to AS 43.23.005(d) [ineligibility due to conviction or incarceration], or forfeited dividends under AS 43.23.035(a) or (c) [ineligibility due to fraud or aiding an ineligible collection of a dividend], and who is (A) an adult relative in a full, half, or step relationship, or is a legal guardian;
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(e) An application for a dividend may be filed on behalf of a child only by the adult resident through whom the child claims residency, or by another authorized representative.
. AS 43.23.008(c) ("'This subsection does not apply to an absence under (a)(9) or (10) of this section [creating allowable absences for members of the United States Congress and their staff members] or to an absence under (a)(13) of this section [creating allowable absences for spouses and dependents of allowably absent individuals] if the absence is to accompany an individual who is absent under (a)(9) or (10) of this section.").
. Harrod v. State, Dep't of Revenue,
. Id. (citing Eagle v. State, Dep't of Revenue,
. Hidden Heights Assisted Living, Inc. v. State, Dep't of Health & Soc. Servs., Div. of Health Care Servs.,
.
.
. City of New Orleans v. Dukes,
.
. See State v. Anthony,
. Zobel,
.
. Id. at 1127.
. At the time Church was denied a dividend, AS 43.23.095(8), the statute defining allowable absences included seven categories of allowable absences, plus an eighth subpart "allow[ing] for excusable absences for other reasons which the [Department of Revenue] commissioner may establish by regulation." Id. at 1127-28 (citations and internal quotation marks omitted). Pursuant to this catch-all, 15 AAC 23.163(c) listed 16 separate categories of allowable absences, none of which covered Church. Id. at 1128. Church was therefore arguing that it was a Department of Revenue regulation, and not a statute, that was constitutionally infirm. Nonetheless, the constitutional analysis would be the same for a regulation or a statute.
. Id. at 1130.
. Id. at 1131.
. Harrod v. State, Dep't of Revenue,
. State, Dep't of Revenue, Permanent Fund Dividend Div. v. Bradley,
. See Harrod,
. Church,
. AS 43.23.008(a)(9), (10), & (13).
.
. Id.
.
. Id. (quoting Application of Obermeyer,
. Pfeifer v. State, Dep't of Health & Soc. Servs., Div. of Pub. Assistance,
. Ross also suggests briefly that the congressional exception violates substantive due process because it "was proposed under dubious circumstances that frustrated the original intent and sponsor of"" the house bill that ultimately became the statutory amendment including the ten-year
.
. Ch. 44, § 5, SLA 1998.
.
. Id. at 440 n. 18 (citations and internal quotation marks omitted).
. Id. at 440 (citing Zeman v. Lufthansa German Airlines,
. Id. at 442 (quoting Brady v. State,
. See Harrod v. State, Dep't of Revenue,
. Benavides v. State,
