The opinion
KENNARD, J., Concurring.
The majority opinion ignores a significant portion of the procedural history of this case. When the full history is examined, we find that the present action is not one to determine child support arrearages, but an action to establish and enforce a previous judgment that has long since become final. To successfully resist enforcement of this final judgment, Ronald Damico (father) must establish not only that he has a valid defense on the merits, but also that there are equitable grounds to set aside the final judgment, and that he has acted with diligence in seeking relief.
The record shows that Mary Damico Austin (mother) obtained an order and judgment for child support in 1960. In 1978, mother commenced proceedings to collect past due installments of child support by personally serving father with a notice that she was seeking arrearages for the years 1960 to 1978. In June 1980, after father had failed to appear at a hearing on mother’s application, the superior court granted judgment against father for over $23,000. In April 1990, mother renewed this judgment. (See Code Civ. Proc., § 683.110 et seq.) With accrued interest, the judgment amount upon renewal was over $34,000. All these proceedings took place in the City and County of San Francisco.
In January 1991, the district attorney for Marin County, acting on mother’s behalf, filed a “Statement for Registration of Foreign Support Order” in the superior court of that county, seeking registration of the 1960 support order and judgment, the 1980 judgment for arrearages, and the 1990 renewed judgment for arrearages. In response, father moved to vacate the registration and to deny enforcement of the support judgments. In support of the latter request, father submitted a declaration stating, among other things, that in 1979, after being served with the notice that mother had applied for child support arrearages, he had retained an attorney to represent him and had then “moved to Arizona believing that this matter had been taken care of by that attorney.” 1 Father also tendered a defense on the merits, as explained in the majority opinion.
*687 Mother submitted declarations stating, among other things, that she had first sought a determination of arrearages in August of 1978. Father retained counsel, and depositions were scheduled for November 1978, but the depositions were canceled when father retained new counsel who requested additional time to prepare. In February 1979, father’s attorney conveyed a settlement offer of $1,800. The attorney represented that father had left the state and was experiencing financial difficulties. Mother rejected the settlement offer. Her attorney attempted to get new deposition dates, but none was ever set. On June 2, 1980, mother filed an amended notice of motion to determine arrearages, serving the motion on father’s attorney. The attorney informed mother’s counsel that he was trying to contact father to determine whether father still wished the attorney to represent him. At this attorney’s request, mother rescheduled the hearing from June 13 to June 20. On June 17, the attorney conveyed a new settlement offer from father in the amount of $2,500. Mother rejected the offer. On June 19, the day before the scheduled hearing, the attorney told mother’s counsel that father had not retained him and that he did not think father would be appearing at the hearing. Father did not appear on June 20, and the court granted judgment for mother in the amount she had requested. On June 23, mother served father with the notice of entry of judgment by mailing a copy to a post office box in Scottsdale, Arizona, that she believed father was using, and by mailing additional copies to his parents, his sister, and both of the attorneys who had represented him.
Father offered no additional declarations or other evidence to dispute the facts as stated in mother’s declarations.
The trial court rejected all father’s tendered defenses as legally irrelevant and ordered father to pay the support arrearages. The Court of Appeal reversed. This court granted review. 2
The 1980 judgment converted the unpaid installments of child support into a lump-sum obligation. In the proceeding leading to that judgment, father *688 could and should have presented any defenses he had to justify nonpayment of the individual installments. Accordingly, the judgment necessarily determined that father has no defense on the merits. The judgment’s resolution of this issue is res judicata and must be accepted by the courts of Marin County, and by this court, unless and until father establishes legally sufficient grounds to vacate or set aside the 1980 judgment and the 1990 renewal of that judgment. (See Pratali v. Gates (1992) 4 Cal.App.4th 632, 644 [ 5 Cal.Rptr.2d 733 ] [“In an action on the judgment, the only relevant question is whether the judgment has been satisfied or remains unpaid.”].)
To have a final judgment set aside, a party must show more than a mere error in the judgment or the absence of a full trial on the merits. “[Pjublic policy requires that only in exceptional circumstances should the consequences of res judicata be denied to a valid judgment.” (Rest., Judgments, §118, com. a, p. 571; see also Rest.2d Judgments, § 70, com. a, p. 180.) A court will enforce a judgment, without examining its legal or factual merits, unless a party establishes grounds for relief by one of the procedures provided for that purpose. (8 Witkin, Cal. Procedure (3d ed. 1985) Attack on Judgment in Trial Court, § 1, p. 403.)
After the time for ordinary direct attack has passed (see Code Civ. Proc., § 473 [allowing up to six months to challenge a judgment entered through tiie moving party’s mistake, inadvertence, surprise, or excusable neglect]), a party may obtain relief from an erroneous judgment by establishing that it was entered through extrinsic fraud or mistake. (In re Marriage of Park (1980) 27 Cal.3d 337, 342 [ 165 Cal.Rptr. 792 , 612 P.2d 882 ]; Olivera v. Grace (1942) 19 Cal.2d 570, 575 [ 122 P.2d 564 , 140 A.L.R. 1328 ].) To warrant relief on this ground, the moving party must establish: (1) facts constituting extrinsic fraud or mistake; (2) a substantial defense on the merits; and (3) diligence in seeking relief from the adverse judgment.
The negligence of an attorney retained to handle a matter may constitute extrinsic mistake. (Hallett v. Slaughter (1943) 22 Cal.2d 552, 556-557 [ 140 P.2d 3 ]; see Kulchar v. Kulchar (1969) 1 Cal.3d 467, 471-472 [ 82 Cal.Rptr. 489 , 462 P.2d 17 , 39 A.L.R.3d 1368 ]; 8 Witkin, op. cit. supra, Attack on Judgment in Trial Court, §§ 214-215, pp. 617-620.) Here, father’s allegations—that he retained an attorney to handle the matter and had assumed it was taken care of—may, if proved, be sufficient to establish extrinsic mistake, although mother’s declarations seem to indicate that no attorney negligence was involved and that father had no reasonable basis for believing that the matter had been taken care of. Relief must be denied if the party *689 seeking relief was guilty of negligence in permitting the mistake to occur. (Kulchar v. Kulchar, supra, at p. 473.) As the parties’ allegations have not been subjected to the test of an adversary hearing, it is not possible for an appellate court to determine on the present record whether father can establish extrinsic fraud or mistake.
In addition to establishing facts constituting extrinsic fraud or mistake, father must demonstrate probable error in the final judgments from which he seeks relief. He must show, in other words, “facts indicating a sufficiently meritorious claim to entitle [him] to a fair adversary hearing.” (In re Marriage of Park, supra, 27 Cal.3d 337, 346 ; see also Bennett v. Hibernia Bank (1956) 47 Cal.2d 540, 554 [ 305 P.2d 20 ].) I agree with the majority that father’s allegations of mother’s active concealment, making it practically impossible for father to pay the child support installments as they fell due, are relevant to establish a defense of estoppel or waiver. 3 Again, however, the relevant facts are disputed and the present record is inadequate to determine whether father has a valid defense on the merits.
*690 Finally, father must demonstrate that he has proceeded with diligence to obtain relief from the 1980 and 1990 judgments. Courts require that a party seek relief as soon as reasonably possible after learning of an adverse judgment. (See In re Marriage of Park, supra, 27 Cal.3d 337, 345-346 ; Stiles v. Wallis (1983) 147 Cal.App.3d 1143, 1150 [ 195 Cal.Rptr. 377 ]; In re Marriage of Wipson (1980) 113 Cal.App.3d 136, 144 [ 169 Cal.Rptr. 664 ]; Alexander v. Abbey of the Chimes (1980) 104 Cal.App.3d 39, 48 [ 163 Cal.Rptr. 377 ].) Here, father’s declaration does not reveal when he became aware of the 1980 and 1990 judgments. Mother’s evidence indicates that she attempted to serve him by mail with the 1980 judgment, but the success of this effort presents a factual question. As with the other requirements for equitable relief, due diligence will be an issue for the parties to litigate in the trial court.
Upon remand, the trial court should determine whether the previous judgment was the result of extrinsic mistake, whether father has a substantial defense on the merits, and whether father has exercised diligence in moving for relief from the 1980 and 1990 final judgments. With the understanding that the trial court will undertake these factual determinations and proceed accordingly, I concur in the majority opinion.
Father signed this declaration in the name of Kenneth P. Ali, a name father appears to have assumed when he moved to Arizona.
In a footnote, the majority defends its decision to ignore the legal effect of the 1980 and 1990 judgments. (Maj. opn., ante, p. 677, fn. 1.) According to the majority, the Court of Appeal “rejected mother’s argument that the default judgment precluded raising the concealment defense at this time[,]” but the majority declines comment on this ruling because “the viability of the concealment defense” was “the only issue raised in the petition for review” and the only issue on which this court granted review. (Ibid.)
The majority’s view of the issue before this court is too narrow. This court’s review includes not only the issue specified in the petition for review, but also “every subsidiary issue fairly included in it.” (Cal. Rules of Court, rule 28(e)(2).) Thus, threshold issues concerning mootness, standing, jurisdiction, scope of review, and the like are always necessarily included within our scope of review. Because the viability of the concealment defense in this case cannot be separated from the procedural context in which father seeks to assert it, *688 the effect of the 1980 and 1990 judgments is “fairly included” in the issue on which this court granted review and thus properly before this court.
Because the defense of estoppel is equitable in nature, the trial court should consider all relevant circumstances, including any circumstances that might tend to justify or excuse, in whole or in part, the custodial parent’s concealment Mother’s declaration contains factual allegations that would be pertinent for this purpose. For example, she states that in August 19, 1958, while the divorce proceeding was pending, father was ordered to pay $75 per month as temporary child support. Although fully aware of mother’s whereabouts, father made no effort to comply with the child support order and visited his son only three times in the nine months following the child’s birth. The interlocutory judgment entered on May 19, 1959, included $698.50 in child support arrearages under the interim order, and it required that father pay child support thereafter in the amount of $50 per month. In September 1959, father was adjudged in contempt for failure to pay child support and sentenced to jail for five days. Despite this sanction, he still did not pay support In February 1960, father gave mother a check for $50, but “it did not clear his bank.” After father was released from jail, he telephoned mother and told her he would “take [their] son away from [her] and [she] would never see him again,” and also that he “would move to Mexico where [she] would not find him if [she] did not leave him alone.” Mother took this threat seriously and thereafter “always took great efforts never to let [the child] be alone.” Mother knew that father’s mother is a native of Mexico and had funds to help father relocate to that country. On another occasion, in early 1961, father asked mother “not to bother him for a few years while he attended school,” and he told her “that he expected to get an inheritance when he became 35 years old . . . and that he would pay child support then.” (Elsewhere mother alleges that father was 19 years old in 1958. If so, he would not have been 35 until 1974, just 4 years before mother commenced her collection efforts.)
If the trial court finds that mother intentionally concealed her whereabouts from father, it should also consider the truth of mother’s allegations that father had a history of not paying child support, that he had threatened to abduct the child, and that he had asked mother to defer enforcement of the support obligation until he turned 35 in 1974. Nothing in the majority opinion suggests that facts such as these would be irrelevant to the court’s exercise of its equitable powers.