(concurring) — While I agree with the majority that Ace Hardware is not guilty of marital status discrimination under RCW 49.60 as a matter of law, I fear the majority’s analysis of marital status discrimination may unnecessarily inject confusion into an area of law already settled by this Court in numerous previous cases.
The majority contends RCW 49.60.180 is plain and unambiguous and therefore requires no further construction. Majority op. at 752-53. Nevertheless, the majority then proceeds to construe this “plain and unambiguous” statute in the guise of offering “background factors” which confirm the statute’s plain meaning. Majority op. at 755-57. This additional discussion is unnecessary dicta as we do not construe unambiguous statutes. “ ‘Plain words do not require construction .... This court will not construe unambiguous language.’ ” State v. McCraw, 127 Wn.2d 281, 288, 898 P.2d 838 (1995) (quoting Sidis v. Brodie/Dohrmann, 117 Wn.2d 325, 329, 815 P.2d 781 (1991)).
RCW 49.60.180 is plain and unambiguous in light of our prior analysis of the statute. Because the events of this case all took place prior to the 1993 amendments to RCW 49.60.180,5 our analysis of RCW 49.60.180 and marital status discrimination is governed by our decisions in Washington Water Power Co. v. Washington State Human Rights Comm’n, 91 Wn.2d 62, 586 P.2d 1149 (1978); Kastanis v. Educational Employees Credit Union, 122 Wn.2d 483, 859 P.2d 26, 865 P.2d 507 (1993); and Magula v. Benton Franklin Title Co., 131 Wn.2d 171, 930 P.2d 307 (1997), interpreting both the statute as it existed prior to 1993 and the Human Rights Commission’s regulations associated with that version of the statute. Strangely, the majority opinion ignores this authority and instead cites a case *759interpreting an unemployment compensation statute, RCW 50.20.050(4). Majority op. at 752-53 (quoting Davis v. Department of Employment Sec., 108 Wn.2d 272, 737 P.2d 1262 (1987)).
Our cases make clear the nature of a cause of action for marital status discrimination under RCW 49.60.180. A plaintiff must prove
“ ‘(1) that the employer discriminated against her based on her marital status and (2) that this discrimination was not justified or excused by ‘business necessity’.” Kastanis v. Educational Employees Credit Union, 122 Wn.2d 483, 493, 859 P.2d 26 [(1993), amended, 122 Wn.2d 483,] 865 P.2d 507 (199[4]). Marital status must be a substantial factor in the employer’s adverse employment decision. Mackay v. Acorn Custom Cabinetry, Inc., 127 Wn.2d 302, 310, 898 P.2d 284 (1995).
Magula, 131 Wn.2d at 176. As to the definition of marital status itself, we have approved the Human Rights Commission regulation definition in Washington Water Power, Kastanis, and Magula:
In general, discrimination against an employee or applicant for employment because of (a) what a person’s marital status is; (b) who his or her spouse is; or (c) what the spouse does, is an unfair practice because the action is based on the person’s marital status.
WAC 162-16-150(2).6 However, in Edwards v. Farmers Ins. Co., 111 Wn.2d 710, 763 P.2d 1226 (1988), we cautioned that where mixed factors—both a plaintiffs marital status and other factors—are present, a cause of action is stated against an employer only where the adverse employment action turns on marital status.
*760Turning to the facts in the present case using the tests set forth in RCW 49.60.180 as construed by our cases and WAC 162-16-150(2), Ace Hardware’s policy prohibited employment of relatives, cohabitors, or spouses within the same department or job area where one employee could supervise or influence the other’s job status and advancement. This policy is substantially narrower than the anti-nepotism policies we addressed in Washington Water Power. The antinepotism policies there banned spouses from being employed at the same time by a company, but also permitted the company to refuse to hire a spouse of an employee or to force one of two married employees to terminate their employment. We upheld a Human Rights Commission rule finding such policies to be discriminatory.
In the present case, Ace Hardware’s action against Wag-goner and Cyr turned as much on their lying about their relationship as it did implementation of the policy. Ultimately, Ace Hardware’s policy is based on a fully legitimate concern that people with a personal relationship should not supervise or otherwise influence each other’s job situation. Specifically, Ace’s policy does not turn on marital status as required by Edwards. Whether Waggoner or Cyr was single, divorced, or married, was not a substantial factor in the employer’s adverse employment decision. See Mackay v. Acorn Custom Cabinetry, Inc., 127 Wn.2d 302, 898 P.2d 284 (1995).
Durham, C.J., concurs with Talmadge, J.
The Legislature amended RCW 49.60.180 in 1993. Those amendments are again not before this Court because the events here transpired from 1988 to 1992. Kastanis, 122 Wn.2d at 488 n.3; Magula, 131 Wn.2d at 181. The majority’s reference to the 1993 amendments in construing RCW 49.60.180 (Majority op. at 755) is misplaced. As we said in Maguía, the Legislature may not change the meaning of a statute retrospectively once the Supreme Court has rendered an opinion on the statute’s meaning. Magula, 131 Wn.2d at 182.
Justice Sanders cites his dissent in Maguía as authority for the proposition that Ace Hardware’s conduct is proper because “the employer’s conduct is not proscribed because neither party was married.” Majority op. at 757. I disagree. An unmarried person can state a cause of action under RCW 49.60.180. For example, an unmarried person has a claim against an employer who refuses to hire any divorced person or hires only married people.
The majority focuses unduly on “social relationships” rather than the statutory question of whether the adverse employment decision turned on the question of a person’s status as single, divorced, or married, or the identity or conduct of a person’s spouse.