Arizona Attorney General Kris Mayes is among a coalition of Democratic attorneys general who have filed their 100th lawsuit against the Trump administration, this time targeting the rollback of federal power plant emissions rules. The coordinated legal challenge marks a significant milestone in an ongoing campaign by Democratic-led states to contest executive branch actions across a broad range of policy areas.
Why It Matters
The lawsuit directly challenges federal environmental regulations governing power plant emissions, with implications for air quality standards, climate policy, and energy infrastructure across the country. Arizona and other Democratic-led states argue that the administration’s rollback of these rules undermines legally established environmental protections and the authority of Congress to set emissions standards.
The case adds to a growing body of litigation that has forced federal courts to weigh in on the limits of executive power — a question with lasting consequences for how future administrations can reshape regulatory frameworks without congressional approval.
What Happened
Democratic attorneys general filed their 100th legal challenge against the Trump administration this week, targeting the administration’s effort to roll back power plant emissions regulations. The Democratic Attorneys General Association (DAGA) announced the milestone lawsuit, describing it as part of a coordinated and sustained legal strategy against what member AGs characterize as executive overreach.
Arizona AG Kris Mayes has been a prominent figure in this coalition, participating in public events — including a town hall held in Phoenix in March 2025 — alongside AGs from Minnesota, Oregon, and New Mexico to explain their opposition to administration policies. Since President Donald Trump’s second term began in January 2025, Democratic-led states have pursued legal action across a wide range of issues, including withheld congressional appropriations, immigration enforcement measures, and tariffs on foreign goods.
The emissions rollback lawsuit is the latest in a series of environmental challenges, as the administration has moved to revise or rescind a number of regulations put in place under previous administrations. The specific power plant rules at issue involve emissions standards that environmental advocates say are critical to meeting federal air quality benchmarks.
By the Numbers
100 — Total lawsuits filed by Democratic attorneys general against the Trump administration as of this week.
67 — Number of cases that have received court rulings to date.
55 of 67 — Cases in which Democratic AGs report winning favorable rulings, representing a win rate of approximately 82 percent.
14+ — States represented in the Democratic Attorneys General Association’s coordinated legal efforts, spanning issues from environmental policy to immigration and federal funding disputes.
15+ months — The duration of the legal campaign, which began shortly after President Trump’s inauguration on January 20, 2025.
Zoom Out
The Democratic AGs’ legal campaign is part of a broader national pattern of state-level opposition to federal executive actions. Similar coalitions emerged during Trump’s first term and have become an established mechanism for states to challenge administrative rulemaking and executive orders through the courts.
The emissions rollback challenge fits into a wider national debate over environmental regulatory authority — a debate that has reached the Supreme Court in recent years. The Supreme Court’s recent 8-1 ruling requiring strict scrutiny review in a Colorado conversion therapy case reflects the Court’s continued engagement with questions about the boundaries of government authority, a legal theme also central to the emissions litigation.
Democratic AGs have also pursued legal challenges related to immigration policy, including disputes over asylum and border enforcement. The Trump administration has separately asked the Supreme Court to revive its border turn-back policy in an ongoing asylum fight, illustrating how the executive branch is simultaneously defending its actions on multiple legal fronts.
What’s Next
The power plant emissions lawsuit will proceed through federal court, where a judge will determine whether the administration’s regulatory rollback complied with the Administrative Procedure Act and other applicable federal statutes. Given the pace of prior rulings in this coalition’s cases, a preliminary injunction hearing could come within weeks.
DAGA has signaled it does not intend to slow its litigation pace, and additional lawsuits are expected as the administration continues to advance its regulatory agenda. Arizona AG Kris Mayes is expected to remain an active participant in future coordinated legal actions alongside attorneys general from other Democratic-led states.