Pinal County’s legal team told a judge Friday the dispute over County Attorney Brad Miller’s immigration agreement comes down to a single question: Does he have the authority to sign it at all?

In a reply filed April 3 in Maricopa County Superior Court, the county urged the court to block Miller from taking any action under his 287(g) agreement with federal immigration authorities, arguing he “had no statutory right” to enter into the deal without approval from the Pinal County Board of Supervisors.

The filing supports the county’s motion for a preliminary injunction in its lawsuit challenging Miller’s participation in the federal task force program.

County attorneys with Snell and Wilmer argue Miller “fails to cite a single authority” allowing a county attorney to enter into contracts, particularly one that commits county resources and personnel.

Instead, they wrote, Miller attempts to rely on “implied” powers and claims of federal preemption, arguments the county says “do not address the core problem” that he lacked legal authority to sign the agreement in the first place.

The reply lays out several arguments supporting that claim.

First, it asserts only the Board of Supervisors has the authority to enter into contracts on behalf of the county, citing Arizona law that vests those powers exclusively with the board.

Second, the filing argues the agreement improperly obligates county funds without board approval, rejecting Miller’s position that operating within his approved budget gives him discretion to spend those funds as he chooses.

“A yearly budget is not a personal slush fund,” the filing states.

Third, the county contends the agreement qualifies as an intergovernmental agreement requiring board approval and also infringes on the sheriff’s authority to conduct law enforcement actions such as arrests.

The filing further argues the deal is invalid under federal law because 287(g) agreements may only be entered into by a state or political subdivision, not an individual county officer.

County attorneys also reject Miller’s claim that state law prevents the board from challenging the agreement, writing that requiring proper approval does not restrict immigration enforcement but enforces existing law.

The county asks the court to grant a preliminary injunction barring Miller from acting under the agreement while the case proceeds.

The filing comes three days after Miller asked the court to dismiss the lawsuit, calling it “without merit” and arguing Arizona law supports his authority to cooperate with federal immigration enforcement.

The case remains pending before Judge Michael Gordon. A status conference is scheduled for Thursday.