Robert Burns v. Arizona Public Service Co, 517 P.3d 624

In 2014 elections, allegations arose that APS (via holding company Pinnacle West) made anonymous contributions to commissioners; Burns (then a commissioner) sought APS spending records and issued subpoenas in 2016–2017.
The Attorney General opined that article 15, §4 and A.R.S. §40-241 authorize individual commissioners to inspect PSC books and examine witnesses under oath.
Four other commissioners voted not to fund Burns’ investigation and, in Commission proceedings (a rate case and a rule-making matter), denied Burns’ motions and effectively prevented enforcement of his subpoenas.
Burns sued in superior court for declaratory relief; the court stayed initial proceedings for administrative exhaustion, later dismissed his amended complaints on grounds that enforcement of subpoenas rests with the Commission as a body and that Burns lacked other relief.
The court of appeals affirmed; the Arizona Supreme Court granted review on (1) whether a majority can prevent an individual commissioner from exercising investigatory powers under article 15, §4, and (2) whether a commissioner may seek declaratory relief under the UDJA.
The Supreme Court held that article 15, §4 grants investigatory and subpoena powers to both the Commission and each individual commissioner, and that an aggrieved commissioner may seek relief under the UDJA; the case was reversed and remanded.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Whether a majority of the Commission may bar an individual commissioner from exercising investigatory/subpoena powers under Ariz. Const. art. 15, §4	Burns: §4’s plain text vests investigatory and subpoena powers in "the commission, and the several members thereof," authorizing individual commissioners to issue subpoenas unilaterally	Commission/APS: §3 and §6 give the Commission plenary ratemaking and rulemaking authority; procedural control over proceedings allows the Commission to govern or quash subpoenas and prevent unilateral enforcement	Held for Burns: §4’s language (including "several members") plainly grants investigatory/subpoena authority to individual commissioners; Commission rules cannot abrogate that constitutional grant, though subpoenas remain subject to constitutional limits and judicial review
Whether an aggrieved commissioner may obtain declaratory relief under the UDJA to enforce investigatory rights	Burns: UDJA permits any person whose rights are affected to seek construction/validation of statutes and declarations of rights; he may challenge obstruction of §4 rights	Commission/APS: argued declaratory relief was inappropriate or that Burns failed to exhaust remedies; courts below denied relief	Held for Burns: UDJA applies; an aggrieved commissioner may seek declaratory relief in superior court; remanded for further proceedings as appropriate

Polaris Int'l Metals Corp. v. Ariz. Corp. Comm'n, 133 Ariz. 500 (1982) (Commission has broad investigatory authority; courts may curb administrative investigations)
Johnson Utils. v. Ariz. Corp. Comm'n, 249 Ariz. 215 (2020) (describing the Commission’s plenary ratemaking authority and constitutional limits)
City of Surprise v. Ariz. Corp. Comm'n, 246 Ariz. 206 (2019) (indirect assertion of regulatory authority can confer standing)
Sun City Home Owners Ass'n v. Ariz. Corp. Comm'n, 252 Ariz. 1 (2021) (Commission authority subject to constitutional constraints and judicial review)
Residential Util. Consumer Off. v. Ariz. Corp. Comm'n, 240 Ariz. 108 (2016) (describing the test-year concept and rate-setting framework)
Morrissey v. Garner, 248 Ariz. 408 (2020) (principles of constitutional text interpretation; give effect to every word)