PHOENIX — Arizona Public Service went to court Friday to push back against a subpoena demanding it produce records disclosing any spending in the 2014 Corporation Commission election that saw deep involvement by dark money groups.

The utility took two actions late Friday to block the effort by Arizona Corporation Commissioner Bob Burns to untangle how Arizona Public Service might have influenced the election.

APS and its parent company, Pinnacle West Capital Corp., asked a judge to declare the subpoenas invalid, warning that it’s willing to go to the U.S. Supreme Court if necessary. It also asked the Arizona Corporation Commission to quash the subpoenas.

In its court filing, the utility cited the landmark Citizens United ruling at the U.S. Supreme Court in 2010 that opened the door to unlimited political spending by outside organizations.

The utility has been the subject of ongoing speculation that it spent $3.2 million backing the 2014 elections of two commissioners. The company won’t confirm or deny that it contributed to groups backing the candidates.

“These subpoenas are unlawful, not related to the stated purpose, and are an inappropriate use of subpoena power,” said Barbara Lockwood, vice president of regulation for APS.

The spending in the 2014 election focused heavily on the presence of rooftop solar in the state.

Burns has said the alleged campaign contributions make the public look at the commission “with suspicion and mistrust.” He said Friday that he was reviewing the documents.

The commission regulates electricity providers, water companies and other firms that hold monopoly power in the state, including setting rates. It also oversees securities regulation, railroad and pipeline safety and facilitates business incorporation. It has executive, judicial and legislative power over the firms it regulates.

Attorney General Mark Brnovich in May issued a legal opinion that said a single commissioner can require regulated utilities to disclose whether they spent money to influence an election.

Burns, who is running for re-election, has been rebuffed by the other four commissioners in his effort to hire an outside attorney to analyze how outside interests may be influencing utility regulators’ decisions.