Justices on the Maine Supreme Judicial Court appeared Tuesday to challenge the legal argument that Portland voters lack the authority to set a higher minimum wage for workers in the city than the one the state has adopted.

But the justices also seemed to agree with a lower court’s ruling that the voter-approved minimum wage – and a provision for time-and-a-half pay for minimum wage earners working during an officially declared emergency – did not take effect 30 days after the vote, as proponents of the ordinance intended.

In November, more than 60 percent of city voters approved raising the minimum wage in Portland from $12 an hour to $15 an hour by 2025. The initiative also included a provision to increase the minimum by 50 percent for those who work in the city during declared emergencies, such as the current statewide pandemic emergency. That would raise Portland’s minimum wage to $18 an hour, at least as long as the emergency declaration remains in effect.

The Portland Regional Chamber of Commerce sued less than a month after the referendum passed, arguing that setting a higher minimum wage is beyond the authority of city voters. The chamber also contends the law shouldn’t take effect this year, which would negate any immediate impact of the emergency pay provision.

In February, a Superior Court justice ruled that the minimum wage ordinance is valid, but he also said its provisions don’t take effect until Jan. 1, 2022.

The chamber appealed that decision to the state Supreme Court. The ruling also was appealed by a lawyer representing two workers who intervened in the lawsuit to challenge the 2022 effective date. The Supreme Court held a hearing on the appeals Tuesday.

The justices did not indicate when or how they will rule, but they appeared to question the chamber lawyer’s argument that setting a minimum wage and approving the emergency wage provision exceeded voters’ authority.

The lawyer, John J. Aromando, asked the court to be a “guardian of the Maine Constitution,” and rule that the initiative went beyond voters’ authority, rather than follow the political “mood of the moment.” Aromando said he agrees that cities can adopt minimum wages that exceed the wage set by the state, but argued that voters can’t do so through a referendum.

Aromando also argued that under the Maine Constitution, municipal referendums can deal only with municipal matters. Minimum wages are a shared state and municipal matter, he said, and therefore can’t be addressed in a referendum.

Those justices who asked questions, however, said the court has always held a liberal view of citizens’ initiatives to encourage participatory democracy.

Many employers are abiding by the wage referendum because they are concerned that if the law is eventually upheld and already in effect, they could be sued by workers for back wages and damages.

As to the ordinance’s effective date, the justices seemed to suggest that the referendum was worded in a confusing manner, leaving it unclear whether its provisions should apply immediately, next year, or even in 2025, when the final step increase in the minimum wage will take effect.

Shelby H. Leighton, the lawyer for the two workers, conceded that the wording could be confusing, but she said it was clear enough for voters to understand that the ordinance would take effect 30 days after the vote.