Some Key legislation

• Banned sex changes on minors

• Eliminated a state agency

• Passed universal occupational licensing

• Eliminated pensions for politicians

• Protected Independent Contractor status

• Passed tougher laws against terrorism

• AZ Ice Act

• Eliminated the tenant paid rental tax

Litigation as President of the Arizona State Senate

Under Arizona Revised Statutes § 12-1841 and pursuant to Arizona State Senate Rule 2(N), the President of the Arizona Senate plays a critical role in upholding Arizona laws and maintaining the separation of powers between branches of government.

Some of the notable litigation involvement by Petersen as President of the Arizona Senate include:

• President Petersen is the lead party in defending Arizona’s “Save Women’s Sports Act” — which bans biological males from competing in women's and girls' athletic events in Arizona public schools — after Attorney General Mayes refused to defend the law in court. 

• Defending Arizona election laws requiring (1) proof of citizenship and proof of residence in the state when registering to vote and (2) county recorders to provide notice to registrants who have not provided documentary proof of citizenship. On August 22, 2024, the U.S. Supreme Court affirmed that new voters who are registering with a state form must provide proof of citizenship in order to cast a ballot.

• Filing amicus briefs at the US Supreme Court opposing the Ninth Circuit’s decision in Johnson v. City of Grants Pass, which effectively held that the Eighth Amendment prohibits governments from disbanding homelessness encampments. On June 28, 2024, the US Supreme Court ruled in favor of the position advocated by Petersen and held that the enforcement of generally applicable laws regulating camping on public property does not constitute “cruel and unusual punishment” prohibited by the Eighth Amendment.

• Defeating Governor Katie Hobbs in court after she attempted to bypass Senate confirmation by leaving agency directorships vacant and refusing to nominate individuals unless the Senate changed its internal procedures. Petersen won the lawsuit on August 12, 2024 after Governor Hobbs admitted that she violated state law by refusing to nominate directors.

• Suing President Biden to stop his designation of nearly 1 million acres as a national monument in northern Arizona— which had the effect of halting all mining, ranching, and other local uses of the land.

• Challenging Biden's executive order forcing federal contractors and their employees to receive the COVID-19 vaccine or risk losing their job. The case concluded on December 28, 2023  in victory for President Petersen and the Arizona Senate, after the Ninth Circuit vacated its ruling upholding the vaccine mandate.

• Joining with 25 states in asking the US Supreme Court to overturn the Colorado Supreme Court ruling barring President Trump from the 2024 presidential primary ballot. The US Supreme Court unanimously reversed the Colorado Supreme Court, vindicating the position taken by Petersen.

• Joining with the Arizona Chamber of Commerce and Industry in a lawsuit against the Environmental Protection Agency (EPA) challenging a Biden Administration rule that creates unattainable environmental PM 2.5 standards in Arizona.

• Joining with the Arizona Truckers Association in lawsuits challenging two new rules issued by the EPA under the Biden Administration that would require, by 2032, nearly 70% of all new vehicles and 25% of all new semi trucks sold in the United States to be electric.

• Defeating a lawsuit brought by Attorney General Mayes in which she asserted control over Arizona’s budget process.  The court also awarded the Legislature over $40,000 in attorneys fees against Attorney General Mayes.