You have requested our assistance in determining the marital status of Henrietta C~,
                  an applicant for spouse's benefits. Ms. C~ has filed alternative applications on the
                  accounts of two retired wage earners, Paul A~, a California domiciliary, and Virgil
                  N~, domiciled in Ohio. You have concisely summarized the pertinent facts, as follows:
               
               Mr. A~ married Ms. C~ in 1937, left her in 1939, returned for four months in 1946,
                  and then left her again. She has not seen him since. Mr. A~ obtained a void Mexican
                  divorce 1/15/47 and states he thought his lawyer contacted Ms. C~ about it. He remarried
                  1/28/47. Ms. C~ reports that she did not receive notice but that, in 1947 or 1948,
                  she heard indirectly (through a cousin) that Mr. A~ had divorced her and remarried.
               
               In 12/55, Ms. C~ began cohabiting with Virgil N~ in Ohio, while he was still married
                  to a prior wife. He divorced the prior wife in 1/67. Thus, from 1/67 until now, Mr.
                  N~ and Ms. C~ believed themselves free to marry and have continued in their common-law
                  relationship. They have held themselves out as man and wife, conducted their business
                  as man and wife, and referred to each other as a common-law spouse in Wills drawn
                  up in 1978. Barring a short period in Michigan the two have been domiciled in Ohio
                  throughout their relationship.
               
               Your initial question is whether Ms. C~ is estopped from questioning the validity
                  of the invalid divorce decree. Insofar as this issue relates to Ms. C~ entitlement
                  on Mr. A~ account, it must be resolved based on the laws of his state of domicile,
                  California. Section 216(h) (1) (A) of the Social Security Act; 20 C.F.R. ยง404.345.
                  "[I]t has frequently been held in California that where a spouse, although wholly
                  innocent of the procuring of a divorce decree. by the other spouse, remarries in reliance
                  thereon, he or she is estopped to question the validity of the divorce on jurisdictional
                  grounds." In Re Marriage of Toth, 38 Cal. App. 3d 205, 212, 133 Cal. Rptr. 131, 136(1974). In this case, although
                  Ms. C~ took no part in the defective divorce proceedings, she nevertheless attempted
                  to establish a common law marriage in reliance upon the Mexican decree. This reliance
                  now prevents her from challenging the decree.
               
               You question whether the estoppel doctrine applies where, as here, the reliant spouse
                  had only indirect information about the divorce proceedings or where, also as in this
                  case, the marriage was by common law. The doctrine of estoppel in this context is
                  based on the principle that one cannot "take the benefits of a divorce decree when
                  it suits his purpose and then reverse his position and repudiate the divorce decree
                  on the ground that it is void for want of jurisdiction (even though it may be) when
                  it is no longer profitable or to his advantage to do so." Id. Accordingly, estoppel is properly invoked whenever the' spouse to be estopped has
                  sought to benefit from a divorce decree by remarriage. As long as the intent to benefit
                  is present, the degree of knowledge concerning the divorce proceedings is immaterial.
                  The consequences of estoppel cannot be avoided merely because the party to be estopped
                  carelessly relied on rumors or otherwise failed to make an adequate investigation
                  of the matter. Smith v. Smith, 157 Cal. App. 2d 46, 320 P.2d 100, 102 (1958); GC opinion re Phil W. H~ D-3973,
                  August 12, 1958. 1_/
               
               You next ask how the recent enactment of section 78(c) of California's Probate Code
                  affects the estoppel doctrine as applied to divorce. The statute, which became operative
                  on January 1, 1985, provides that, for probate purposes, the term "surviving spouse"
                  does not include "[a] person who, following a decree or judgment of dissolution or
                  annulment of marriage obtained by the decedent, participates in a marriage ceremony
                  with a third person." As indicated by the Law Revision Commission Comment to this
                  addition, the provision merely was intended to be consistent with the prior California
                  law of estoppel as developed by the courts. (.Reprinted in West's Annotated Cal. Codes,
                  Probate Code, Vol. 52, 1985 Cumulative Pocket Part, following section 78, at 24-25.)
                  Your assumption that section 78 does not identify every circumstance where estoppel
                  may apply is correct. Thus, in answer to your specific questions, estoppel still applies
                  to participants in common law as well as ceremonial marriages and to third parties
                  relying upon a void divorce.
               
               Your final question about California law is whether there have been any changes in
                  the approach to laches since the issuance on May 11, 1978 of our opinion re Howard
                  C. E~ The equitable defense of laches may be invoked against a party who has failed
                  to assert his/her rights in a timely fashion, causing thereby some detriment or prejudice
                  to another. This venerable doctrine has not been modified recently. Our latest discussion
                  of laches is contained in GC opinion re John J~, March 11, 1986.
               
               Inasmuch as Ms. C~ status for purposes of her claim on Mr. N~ account is governed
                  by Ohio law, you also want to know whether, based on the foregoing legal and factual
                  circumstances, Ms. C~ would be treated as Mr. N~ wife under Ohio law. We are unable
                  to answer this question because Ohio lies outside our Region. Therefore, we are forwarding
                  your memorandum, along with the claims files, to the appropriate Regional Counsel's
                  Office (Region V, Chicago, Illinois) for response. That office will be corresponding
                  with you directly.
               
               1_/ Both these cases involved the estoppel of a "spouse" who married a party to a
                  prior invalid divorce. As these cases suggest, the key to estoppel applies (in the
                  absence of countervailing circumstances such as undue influence, Fraud, incapacity),
                  whether the person subject to estoppel was a party to the defective divorce or a subsequent
                  "spouse."