Arizona Attorney General Mark Brnovich will soon rule on whether cities can impose restrictions on dark money in local campaigns.

Sen. Vince Leach alleged Tempe violated a state law prohibiting local governments from requiring tax-exempt organizations from registering as political committees in 2017 by passing a voter approved ordinance banning dark money contributions.

The law allowing a legislator to demand an attorney general to investigate complaints applies only to ordinances, regulations or other official action adopted or taken by the governing board of a county, city or town.

It is unclear if the authority extends to this voter-approved measure referred to the ballot by Tempe City Council.

Tempe’s dark money ordinance was signed by Gov. Doug Ducey in 2017, as constitutionally required, but he noted it may soon be superseded by state law.

The ordinance in question requires any group spending more than $1,000 during an election cycle to disclose the original source of contributions.

The Office of the Attorney General has 30 days to decide if the complaint has merit.

Tempe City Council will vote next month on whether to send a ballot measure to voters next March seeking tighter restrictions on independent expenditures.

The Sunshine Ordinance would require groups making independent expenditures over $1,000 to disclose their organization name and source of funding. Tempe has not seen an uptick in independent expenditures yet but wants to prevent a future increase as independent expenditures are often associated with mud-slinging and attack ads.

The Mayor’s office and the Tempe Chamber of Commerce have expressed concern over the Sunshine Ordinance, worrying it might cause legal trouble for the city for infringing on first amendment rights and the Citizens United decision.

Even if the measure is approved by voters, as a charter amendment it will be automatically reviewed by the state to ensure there is no conflict with state law.