Not all states have a rule, as apparently MS does, that requires a judge to render a decision within a specific period of time. For those that do, that would bolster the use of a mandamus request because the moving party can show that there is a nondiscretionary act that the law requires the judge to do, i.e. issue an opinion within a specific period of time. But New Mexico has no such rule. Mandamus is an extraordinary remedy in New Mexico. The standard, as stated by the NM Supreme court is as follows:
Originally Posted by latigo
“Mandamus is a drastic remedy to be invoked only in extraordinary circumstances. Indeed, mandamus lies only to force a clear legal right against one having a clear legal duty to perform an act and where there is no other plain, speedy and adequate remedy in the ordinary course of law.” Richardson, 2007–NMSC–023, ∂ 9, 141 N.M. 657, 160 P.3d 566 (internal quotation marks and citation omitted).
Quality Auto. Ctr., LLC v. Arrieta, 2013-NMSC-041, ∂ 19, 309 P.3d 80, 84. So I ask you, in the absence of a set deadline for the judge to issue an opinion, what clear legal right does the OP have to have an opinion issued in eight months time? I have found no court cases in which the NM courts have ordered mandamus to a trial court merely to speed up issuing an opinion. Instead, what I have found is an opinion that strongly suggests to me that the effort, at least after only eight months, would not succeed:
Torres cites to no statute or case law that imposes a specific time limit on judges to dispose of cases. He grounds his argument in two portions of the New Mexico Rules of Civil Procedure calling for “speedy” determinations and a resolution of cases “promptly” and “efficiently.” Rule 1–001(A) NMRA; Rule 21–300(B)(8) NMRA. Both rules are certainly open to interpretation and judicial discretion, depending on context. Torres points to out-of-state authority—an Arkansas case in which the opinion of a foot-dragging judge was sent to the state's disciplinary committee for consideration and a West Virginia case in which a judge who had delayed a ruling for 33 months was ordered to issue one within 30 days. A second West Virginia case similarly resulted in a writ of mandamus ordering a decision to be rendered after a delay of 17 months. None of the lower court decisions in those cases were overturned. If anything, Torres's argument highlights the fact that at no time during the nearly 16 months between the end of trial and the issuing of findings of fact and conclusions of law did he file a motion with the district court seeking a resolution or a petition at the appellate level seeking a writ of mandamus. In fact, for the first two months after the trial, the district court had not even received Torres's own proposed findings of fact and conclusions of law.
Further, Torres provides no evidence of true prejudice that resulted from the delay of more than a year. The only finding of fact he can challenge in the district court's ruling is that the court confused an exchange of small bills for large bills with an exchange of coins for bills. Thus, no material error was made by the district court in rendering its findings of fact and conclusions of law. Therefore, we decline to overturn the verdict in these circumstances.
Torres v. Montano, No. 30,207, 2012 WL 868941, at *8–9 (N.M. Ct. App. Feb. 20, 2012). So while I agree that the use of mandamus would not be “inappropriate” as you put it, I do think it is extremely difficult to win such a request, especially given that there is no case law in NM supporting mandamus in that context. As the quoted section of the Torres case illustrates, the appellant had to look hard to find cases in other states to support that the delay was a problem, and the NM court did not seem to think much of those and, moreover, the court expressly found that a 16 month delay — twice as long as the time so far involved here — was not in any way prejudicial to the appellant. Thus I remain of the view that, at least in the jurisdictions I'm familiar with that such a request is a poor way to achieve the goal of getting an opinion issued more promptly. Perhaps if the delay was truly extraordinary it would be worth a shot, but at least in NM I don’t think a delay of eight months rises to that level.
I would therefore suggest to the OP he consult a New Mexico attorney about this before venturing off into a writ request that may fail and may just simply add more time and cost for him/her in this litigation.