Defamation Update: Will the Anti-SLAPP Statute Get Slapped Down?

By Robert H. Feinberg, Ian Joyce, and Thomas Williams

In a move that may fundamentally alter defamation litigation in Arizona, Maricopa County Attorney Rachel Mitchell in State v. Koert recently requested that the Maricopa County Superior Court declare Arizona’s anti-strategic lawsuit against public participation (anti-SLAPP) statute unconstitutional.¹

Arizona is one of 38 states that has an anti-SLAPP statute, designed to protect First Amendment rights. The statute allows a defamation defendant to quickly move to dismiss the case and request compensation for their attorney’s fees, rather than suffer through protracted litigation. A person sued for exercising their First Amendment rights may file a “motion to dismiss or quash” the lawsuit within 60 days.² If the lawsuit was “substantially motivated by a desire to deter, retaliate against or prevent the lawful exercise of a constitutional right,”³ then the Court can dismiss the lawsuit after an initial hearing.⁴ This process is relatively speedy and much less costly than litigation and trial.

Arizona’s anti-SLAPP statute applies to both civil and criminal cases. Only in Arizona can a criminal defendant seek to have their indictment dismissed under this statute — and it applies where prosecutorial authorities are “substantially motivated” by a desire to deter, retaliate against, or prevent the lawful exercise of a constitutional right.⁵

The Maricopa County Attorney’s Office (MCAO) charged Ms. Koert, along with 67 other defendants, with criminal trespass stemming from a pro-Palestine protest at Arizona State University’s Tempe campus in April 2024.⁶ Koert moved to dismiss the indictment under the anti-SLAPP law on the ground that the charging decision interfered with her right to protest.⁷ The Justice Court found that Koert had met her initial “prima facie” burden under the anti-SLAPP law and ordered an evidentiary hearing, shifting the burden to MCAO to justify its charging decision.⁸ As part of that evidentiary hearing, the Justice Court allowed Koert to issue a subpoena requiring Rachel Mitchell and her Deputy County Attorneys involved in the charging decision to testify about their motivations in making the decision to prosecute Koert.⁹

The County Attorney filed a petition for special action in Maricopa County Superior Court, seeking to prevent the evidentiary hearing. Although the County Attorney argues primarily that the Justice Court had misapplied the anti-SLAPP law, she also asserts “in the alternative” that the anti-SLAPP “statute is unconstitutional as a whole.”¹⁰ The County Attorney argues that the term “substantially motivated” in the anti-SLAPP statute is unconstitutionally vague and overbroad, because it creates inconsistent outcomes and would invalidate otherwise legal regulations on First Amendment speech that have been upheld, like reasonable “time, place, and manner” restrictions.¹¹

The Superior Court has not yet decided whether to grant the petition. But on October 22, 2025, Arizona Attorney General Kris Mayes (the “A.G.”) filed an amicus curiae brief in support of the County Attorney. Within the amicus brief, the A.G. argued that the anti-SLAPP law’s “novel” requirement for a defendant to make a “prima facie” showing that a lawsuit was “substantially motivated” to deter, retaliate for, or otherwise prevent the lawful exercise of First Amendment rights, has “created substantial confusion” and has allowed courts to employ “varying standards to decide cases.”¹² The A.G. also raised concerns that the anti-SLAPP statute would severely delay criminal cases involving anti-SLAPP claims.¹³

The Koert matter is one to watch and will be consequential. We expect that no matter how the Superior Court rules, the case will eventually find its way up through the Arizona appellate courts, and we intend to keep a close watch along the way.