NAHMIAS, Justice.

This is the second appearance of this case in this Court. In Southern LNG, Inc. v. MacGinnitie, 290 Ga. 204, 719 S.E.2d 473 (2011) (Southern I), we reversed the Fulton County Superior Court's dismissal, on the ground of sovereign immunity, of Southern LNG, Inc.'s complaint for declaratory judgment and mandamus, which sought to compel State Revenue Commissioner MacGinnitie to recognize Southern as a "public utility" and to accept Southern's ad valorem property tax returns pursuant to OCGA §§ 48-1-2(21) and 48-5-511(a). On remand, the trial court granted summary judgment to the Commissioner on the mandamus claim, on the ground that Southern has an adequate alternative remedy in the form of tax appeals brought under OCGA § 48-5-311. The court said that Southern could raise, and has raised, its statutory claim that it is a public utility required to return its property to the Commissioner rather than to Chatham County in appeals of the county's tax assessments to the county board of equalization and then to the Chatham County Superior Court.

As explained below, the trial court's analysis was incomplete. To preclude mandamus, an alternative legal remedy must be "`equally convenient, complete and beneficial'" to the petitioner. North Fulton Med. Ctr., Inc. v. Roach, 265 Ga. 125, 127-128, 453 S.E.2d 463 (1995) (citation omitted). The record as developed thus far contains little information about the Chatham County tax appeals, but it is undisputed that the Commissioner is not currently a party to those actions. As a nonparty, the Commissioner normally would not be legally bound by any ruling there on the statutory issue that Southern has raised; indeed, even an appellate court ruling in those cases would not formally and enforceably bind the nonparty Commissioner. Thus, the Chatham County tax appeals, as currently constituted, appear not to provide Southern with an adequate alternative to mandamus.

But that does not necessarily mean that Southern's mandamus action may proceed, because it is unclear whether the Commissioner could be made a party to the Chatham County tax appeals or otherwise become legally bound by them, whose burden it would be to do so, and whether procedural barriers or other features of the tax appeal process would prevent Southern from obtaining a binding ruling on the statutory issue at the heart of this case. The parties have not briefed these issues here or below; the trial court did not address them; and this Court should not try to resolve them in the first instance. Accordingly, we vacate the trial court's grant of summary judgment to the Commissioner and remand the case for further proceedings.

1. Elba Island sits in the Savannah River in Chatham County. Southern owns and operates a facility on the island, where liquefied natural gas (LNG) is unloaded from ships, re-gasified, and then placed into interstate pipelines. The Elba Island facility began operations in 1978, and Southern started filing its ad valorem property tax returns with Chatham County at that time. In 2002, Southern first contacted the Commissioner to request that it be permitted to file its property tax returns with the Commissioner rather than the county, but the Commissioner refused. Southern also appealed the county's ad valorem tax assessments for the years 2003 through 2010 to the county board of equalization and then to the Chatham County Superior Court, arguing both that the county's assessed values were incorrect and that Southern's property should be valued only by the Commissioner.1

In 2010, Southern filed a complaint in Fulton County Superior Court against the State Revenue Commissioner in his official capacity.2 The case was properly venued in Fulton County under OCGA § 48-2-1, which provides that "[t]he official and legal office of the department [of revenue] and of the [state revenue] commissioner shall be in Fulton County." The complaint sought a declaratory judgment that Southern is a "gas" company and therefore a "public utility" under OCGA § 48-1-2(21),3 and thus that Southern must file its ad valorem tax returns with the Commissioner rather than the county pursuant to OCGA § 48-5-511(a).4 The complaint also sought a writ of mandamus to compel the Commissioner to accept Southern's property tax returns.

Along with his answer, the Commissioner filed a motion to dismiss, arguing, among other things, that the entire action was barred by sovereign immunity and that the mandamus claim was additionally barred because Southern has an adequate alternative remedy in the form of tax appeals brought under OCGA § 48-5-311. Southern filed a motion for summary judgment on the merits. The trial court dismissed Southern's complaint as barred in its entirety by sovereign immunity and thus did not rule on Southern's summary judgment motion. Southern appealed, and in Southern I we reversed the dismissal order, holding that at least the mandamus claim was not barred by sovereign immunity. See Southern I, 290 Ga. at 205, 719 S.E.2d 473.

After remand and completion of discovery, Southern renewed its summary judgment motion, and the Commissioner filed a cross-motion for summary judgment. On April 3, 2013, the trial court denied Southern's summary judgment motion and granted summary judgment to the Commissioner on Southern's mandamus claim.5 The court held that Southern had an "acceptable" alternative remedy precluding mandamus by way of an appeal from any final tax assessment by Chatham County to the county board of equalization and then the Chatham County Superior Court under OCGA § 48-5-311.6 Southern again appealed to this Court. See Ga. Const. of 1983, Art. VI, Sec. VI, Par. III(5) (giving this Court general appellate jurisdiction over "[a]ll cases involving extraordinary remedies" like mandamus); OCGA § 9-11-56(h) (authorizing an immediate appeal from "an order granting summary judgment on any issue or as to any party").7

At oral argument, we requested additional briefing on two questions: (1) whether Southern would face any actual harm if the Commissioner refused to accept its tax returns, even if legally required to do so; and (2) whether the Chatham County tax appeals constitute an adequate legal remedy precluding mandamus if the Commissioner will not be legally bound by the judgments there. Both parties filed supplemental briefs.

2. We start by confirming that Southern has standing to seek a writ of mandamus against the Commissioner under OCGA § 9-6-24, which says:

See, e.g., Rothschild v. Columbus Consol. Govt., 285 Ga. 477, 479, 678 S.E.2d 76 (2009) ("`OCGA § 9-6-24 confers standing to seek the writ in those cases wherein the defendant owes a public duty which the plaintiff, as a member of the public, is entitled to have enforced.'" (citation omitted)); Head v. Browning, 215 Ga. 263, 266-267, 109 S.E.2d 798 (1959) (applying the broad statutory standing rule for mandamus to a petition for injunctive relief against the State Revenue Commissioner).

Moreover, Southern has a special interest in enforcing the Commissioner's alleged public duty to accept returns from public utilities, thereby resolving the ongoing uncertainty about where Southern is required to file its tax returns and the amount of taxes that Southern ultimately will be required to pay.8 Contrary to the Commissioner's suggestion, a ruling in the county tax appeals that Southern must return its property to the Commissioner rather than to the county would not relieve Southern of its obligation to pay property taxes if the Commissioner then refused to accept the returns. See OCGA § 48-2-18(e).9

3. We turn next to the question of whether Southern's mandamus claim against the Commissioner is precluded by Southern's tax appeals in Chatham County.

(a) Mandamus is a remedy for improper government inaction — the failure of a public official to perform a clear legal duty. See Scarborough v. Hunter, 293 Ga. 431, 434-435, 746 S.E.2d 119 (2013). As relevant here, the general mandamus statute says:

OCGA § 9-6-20. OCGA § 48-5-511(a) requires the Commissioner to accept ad valorem tax returns from "public utilities" as defined in OCGA § 48-1-2(21) and then to determine, in conjunction with the State Board of Equalization, the fair market value of their property. See McLennan v. Undercofler, 222 Ga. 302, 306, 149 S.E.2d 705 (1966) ("The State Revenue Commissioner has the duty of receiving returns for ad valorem taxes from public utilities and the duty of reviewing and correcting such returns.").10 Thus, if Southern truly is a "public utility" to which OCGA § 48-5-511(a) applies, an action for mandamus could be a remedy to compel the Commissioner to accept Southern's property tax returns.

In granting summary judgment to the Commissioner, the trial court relied on the general rule that mandamus is unavailable where the petitioner has another adequate legal remedy. See OCGA § 9-6-20; North Fulton Med. Ctr., Inc. v. Roach, 265 Ga. 125, 127-128, 453 S.E.2d 463 (1995); Carnes v. Crawford, 246 Ga. 677, 678, 272 S.E.2d 690 (1980). The court pointed to the availability of an appeal of the county's tax assessments under OCGA § 48-5-311, noting that Southern could raise (and has raised) its arguments regarding OCGA §§ 48-1-2(21) and 48-5-511(a) in appealing Chatham County's final assessments for the years 2003 to 2010 first to the county board of equalization and then to the Chatham County Superior Court, where the appeals were still pending.11

However, "[t]he general rule that mandamus does not lie where the petitioner has [another] adequate legal remedy is limited to cases in which the legal remedy is `equally convenient, complete and beneficial.'" Roach, 265 Ga. at 127-128, 453 S.E.2d 463 (citation omitted). The Commissioner is not a party to the Chatham County tax appeals. And

Taylor v. Sturgell, 553 U.S. 880, 884, 128 S.Ct. 2161, 171 L.Ed.2d 155 (2008) (citation omitted). Accord Barham v. City of Atlanta, 292 Ga. 375, 378, 738 S.E.2d 52 (2013). Thus, assuming without deciding that the statutory question of where Southern must file its ad valorem tax returns can be answered in the Chatham County tax appeals, see Southern I, 290 Ga. at 208-210, 719 S.E.2d 473 (Benham, J., dissenting), that answer will not be legally binding on the Commissioner, because he is not now a party to those proceedings. A ruling on the statutory issue that is not binding on the Commissioner is not an adequate alternative to mandamus against him.12

(b) The Commissioner disagrees, invoking the doctrine of stare decisis. The Commissioner argues that if the Chatham County tax appeals result in an appellate court ruling that Southern is a public utility that must file its returns with the Commissioner rather than the county, he would have no credible basis for continuing to refuse to accept Southern's returns. The Commissioner adds that if he still refused to accept Southern's returns at that point, Southern would be authorized to file another complaint for mandamus against him, and the trial court in that proceeding would be required to grant the mandamus based on the binding appellate precedent. See Ga. Const. of 1983, Art. VI, Sec. VI, Par. VI ("The decisions of the Supreme Court shall bind all other courts as precedents."); Art. VI, Sec. V, Par. III ("The decisions of the Court of Appeals insofar as not in conflict with those of the Supreme Court shall bind all courts except the Supreme Court as precedents."). According to the Commissioner, in this way, the Chatham County tax appeals provide Southern with an adequate legal remedy precluding mandamus at this time.

Assuming again that Southern's statutory issue can be properly raised and ruled upon in the Chatham County tax appeal proceedings, the process envisioned by the Commissioner can hardly be described as "`equally convenient, complete and beneficial'" to the present action for mandamus as a means for requiring the Commissioner to accept Southern's tax returns. Roach, 265 Ga. at 128, 453 S.E.2d 463 (citation omitted).13 Beyond its convolutions, there is no assurance that the Chatham County actions will produce a binding appellate precedent on the statutory issue for Southern to invoke in a later mandamus case (and it is noteworthy that the Commissioner does not say that he would abide by a statutory ruling by the Chatham County Superior Court). The county may settle the actions, or choose not to appeal if the superior court rules in favor of Southern, or an appeal may be decided on some other ground. In any of those events, there would be no opinion by the Court of Appeals or this Court for Southern to invoke in a subsequent mandamus proceeding.

More fundamentally, appellate precedents — the decisions of appellate courts on particular legal questions — control the future rulings of lower courts on the same questions, not the legal rights of the parties who appear in those courts, unless the party was bound by the actual judgment in the prior case. A party not so bound is entitled to argue that the precedent should be distinguished or even overruled, understanding that the trial court lacks the authority to disregard precedent and that an argument to overrule therefore must be pursued on appeal, where it will have to surmount the high hurdle of stare decisis. See, e.g., State v. Jackson, 287 Ga. 646, 647, 697 S.E.2d 757 (2010) (overruling a precedent challenged in this way). This is only fair, because a party that was not involved in prior litigation of a legal question may raise arguments and present facts, not offered by the previous parties, that convince the appellate court that its earlier decision was misguided or does not apply to the circumstances of the new case. See Taylor, 553 U.S. at 892-893, 128 S.Ct. 2161 (noting that a nonparty generally has not had a full and fair opportunity to litigate the claims and issues settled in the prior suit and that the application of claim and issue preclusion to nonparties "thus runs up against the `deep-rooted historic tradition that everyone should have his own day in court'" (citation omitted)).14

In short, even if Southern obtained a clear statutory ruling in its favor from this Court in an appeal of the Chatham County actions, that precedent would not be binding on the Commissioner. The Commissioner's adherence to such a ruling might depend on his view of the litigation strategy that Chatham County pursued; moreover, future Commissioners would not be legally bound by their predecessor's informally taken position. Indeed, an announcement by the Commissioner that he now will voluntarily accept Southern's tax returns would not normally render moot Southern's lawsuit to obtain a legally binding ruling to that effect. See WMW, Inc. v. Am. Honda Motor Co., 291 Ga. 683, 685, 733 S.E.2d 269 (2012) (explaining that a defendant's "`voluntary cessation of challenged conduct does not ordinarily render a case moot because a dismissal for mootness would permit a resumption of the challenged conduct as soon as the case is dismissed'" (citation omitted)). Only a judgment that formally and enforceably binds the Commissioner — like a judgment in this mandamus action — would finally resolve the legal issue that Southern has raised.15

The Commissioner cites four cases that he claims support his argument that an adequate legal remedy precluding mandamus need not include the public official against whom mandamus is sought. Those cases are inapposite, however, because they involved plaintiffs who were seeking mandamus against public officials to obtain relief that the plaintiffs could pursue directly.16 Here, by contrast, Southern seeks mandamus against the Commissioner, the sole state official charged with the responsibility of accepting a public utility's tax returns. Southern cannot do on its own what it seeks by mandamus to compel the Commissioner to do, and no other defendant can provide Southern the relief it seeks. As currently constituted, the Chatham County actions may require the county to stop valuing Southern's property, but they cannot require the Commissioner to start doing so. It might take two separate actions to obtain judgments binding on two different defendants; the law does not always limit plaintiffs to only one lawsuit on an issue.

(c) The law does, however, encourage — and sometimes mandate — that all those who may be affected by a judgment be made parties to the proceeding that will produce that judgment, or otherwise be bound by it, because conflicting judgments can produce their own problems.17 As just discussed, the Chatham County proceedings are not an adequate alternative to mandamus if they cannot produce a ruling on Southern's statutory issue that will be binding on the Commissioner. Thus, the trial court erred in granting summary judgment to the Commissioner simply on the ground that the county tax appeals may produce a ruling on the statutory issue. The question remains, however, whether the Commissioner could be made a party to or otherwise legally bound by the Chatham County tax appeals, which could preclude this mandamus action, particularly if that actually occurred or if Southern had the burden of making it happen and failed to do so. See Humphrey v. Owens, 289 Ga. 721, 722, 715 S.E.2d 119 (2011) (explaining that mandamus is barred by the availability of another adequate remedy, even if the petitioner failed to utilize the alternative remedy and it is no longer available).

A tax appeal to superior court pursuant to OCGA § 48-5-311(g) is a special statutory proceeding under the Civil Practice Act ("CPA"). See Spencer v. Lamar County Bd. of Tax Assessors, 202 Ga.App. 742, 743, 415 S.E.2d 332 (1992). The CPA's provisions regarding joinder of parties and similar matters apply in all special statutory proceedings, regardless of any conflict with the underlying statutory scheme. See OCGA § 9-11-81 (requiring application of the CPA as a whole to all special statutory proceedings, except where the statutory scheme expressly prescribes a specific conflicting rule of practice or procedure, but providing that "in any event, the provisions of [the CPA] governing... joinder of parties and causes, making parties, ... interpleader, [and] intervention... shall apply to all such proceedings"). See also Spencer, 202 Ga.App. at 743-744, 415 S.E.2d 332 (holding that OCGA § 9-11-17(a), the CPA provision governing real parties in interest, applies to tax appeals under OCGA § 48-5-311).

Southern and the Commissioner have not briefed, and the trial court has not addressed, whether the CPA rules on joinder of persons necessary for a just adjudication,18 permissive joinder of parties,19 interpleader,20 or intervention,21 or any other procedural devices, allow or require the Commissioner to become a party to, or otherwise become bound by, a judgment rendered on the statutory issue in the Chatham County tax appeals, and whether Southern controls that process or can be or has been thwarted by the Commissioner. These questions may be complicated and may depend on the litigation strategy of the parties. To offer just one example, if the Commissioner were deemed a necessary party in the Chatham County actions, see OCGA § 9-11-19(a), he might — or might not — object to joinder based on venue. If such an objection were made and could be sustained, the Chatham County court would be required to dismiss the Commissioner from the tax appeals, see id., and Southern would be back at square one. Questions of sovereign immunity might also arise again if Southern sought a judgment binding against the Commissioner in the appeals of taxes assessed by the county. These questions should be addressed first by the trial court, with full briefing and whatever development of the record is needed from the parties.22

For these reasons, we vacate the grant of summary judgment to the Commissioner and remand the case to the trial court for further consideration.23

Judgment vacated and case remanded.

All the Justices concur, except MELTON, J., who dissents.

BENHAM, Justice, concurring.

In the original appearance of this case, I issued a dissenting opinion in which I concluded the trial court did not err when it dismissed Southern LNG, Inc.'s petition for writ of mandamus because I believed an appeal before a board of equalization provides an adequate remedy at law for the determination of Southern's question concerning the validity of the county tax assessment. Southern LNG, Inc. v. MacGinnitie, 290 Ga. 204, 206-210, 719 S.E.2d 473 (2011) (Southern I). Upon further consideration of the issue, I agree that it appears necessary to analyze whether this alternative legal procedure is "equally convenient, complete and beneficial," before it can be determined to be an adequate alternative remedy to Southern's mandamus action. See North Fulton Med. Ctr., Inc. v. Roach, 265 Ga. 125, 127-128, 453 S.E.2d 463 (1995). Consequently, I fully concur that summary judgment in favor of the Commissioner must be vacated and the case remanded so that the questions raised by this Court's current opinion may be addressed by the trial court.1

MELTON, Justice, dissenting.

When one takes a closer look at the issue that Southern is truly trying to have addressed, it becomes clear that an appeal before the Chatham County board of equalization pursuant to OCGA § 48-5-311 cannot provide Southern with an adequate remedy at law. The true issue here is not simply whether Southern qualifies as a "public utility" pursuant to OCGA § 48-5-511, but whether Southern can compel the Commissioner to accept its ad valorem tax returns as a public utility pursuant to OCGA §§ 48-1-2(21) and 48-5-511. As the majority points out, here,

Maj. Op. at 691.

Moreover, it remains unclear whether the Commissioner can even be added as a party to the Chatham County actions, and, even if we assume that the Commissioner can be added to such actions, whether any judgment from those actions would be binding against the Commissioner. See Maj. Op. at 693 (Questions regarding whether the Commissioner may be properly added as a party to Southern's Chatham County proceedings "may be complicated," as the Commissioner may object on venue grounds, and "[q]uestions of sovereign immunity might also arise... if Southern sought a judgment binding against the Commissioner in the appeals of taxes assessed by the county"). What seems to be clearer, however, is that the County would be an interested party in any mandamus action against the Commissioner that might affect the County's ability to value Southern for tax purposes. In this connection, although,

(Citation and punctuation omitted.) Gullatt v. Slaton, 189 Ga. 758, 760(1), 8 S.E.2d 47 (1940).

In any event, the lack of certainty regarding any relief that Southern may or may not be able to obtain against the Commissioner in the Chatham County tax appeals certainly begs the question whether the County proceedings can provide a legal remedy to Southern that is just as "convenient, complete and beneficial" as the mandamus action. (Citation and punctuation omitted.) N. Fulton Medical Ctr. v. Roach, 265 Ga. 125, 128(2), 453 S.E.2d 463 (1995). Indeed, it seems that there should be at least some degree of certainty with respect to the adequacy of the remedy at law available to Southern in order for a court to conclude that mandamus is not an available remedy to Southern. See id. ("The general rule that mandamus does not lie where the petitioner has an adequate legal remedy is limited to cases in which the legal remedy is `equally convenient, complete and beneficial'") (citation omitted). Here, we seem to be left only to guess whether the Chatham County tax appeal proceedings "might" be good enough "if" the Commissioner "could" be joined and a binding judgment "could" eventually be entered against him. If we have to resort to such guesswork, I believe that the legal remedy in question simply is not adequate.

The inadequacy of the legal remedy only becomes more pronounced when one considers that, even under ideal circumstances, the Chatham County actions present an unnecessarily inconvenient and roundabout way to address the real issue here, which is to compel the Commissioner to accept Southern's ad valorem tax returns. Specifically, even if the Commissioner could be added to the Chatham County actions (barring venue challenges) and the Chatham County actions could result in a binding judgment against the Commissioner (despite sovereign immunity concerns) based on a finding that Southern was a "public utility," such proceedings simply would not be "equally convenient" to a direct mandamus action against the Commissioner to resolve the true issue presented here.

For all of these reasons, I must respectfully dissent from the majority.