Defending Colorado

Attorney General Phil Weiser and the Colorado Department of Law are working to defend Colorado communities against harmful and illegal actions from the federal government. Please sign up below to receive updates about related actions and events.

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Attorney General Announcements

Lawsuits

Date filed
Coalition of states sue to block mass transfer of Medicaid enrollee data to ICE July 1
Coalition of states sue federal agencies over illegal use of regulation to slash billions in funding June 24
Colorado State University joins lawsuit challenging Department of Defense slashing indirect cost rates for government-funded research (PDF) June 16
Attorney General Phil Weiser joins lawsuit challenging Trump administrationā€™s attack on Coloradoā€™s Clean Car Program June 12
Attorney General Phil Weiser sues ATF to stop return of seized machine gun devices June 9
Attorney General Phil Weiser sues Trump administration over illegal cuts to National Science Foundation funding May 28
Colorado joins lawsuit against Trump administration over illegal immigration conditions placed on infrastructure funding May 13
Colorado joins lawsuit against Trump administration over illegal immigration conditions placed on emergency services funding May 13
Attorney General Phil Weiser sues to stop illegal termination of federal electric vehicle infrastructure funding May 7
Attorney General Phil Weiser sues Trump administration for halting wind energy development May 5
Attorney General Phil Weiser sues to stop dismantling of U.S. Department of Health and Human Services May 5
Gutting of AmeriCorps is the latest AG lawsuit challenging the Trump administration April 29
Attorney General Phil Weiser sues Trump administration over unlawful conditions for K-12 funding April 27
Colorado joins lawsuit to stop Trump administrationā€™s illegal tariffs that are raising prices and creating economic chaos April 23
Attorney General Phil Weiser joins lawsuit to stop dismantling of federal agencies that support libraries, museums, minority-owned businesses and workers April 4
NIH lawsuit – Challenging unlawful grant terminations and delays (PDF) April 4
Attorney General Phil Weiser joins lawsuit against Trump administrationā€™s unlawful executive order seeking to impose sweeping voting restrictions April 3
Attorney General Phil Weiser sues HHS, Secretary Kennedy to overturn illegal public health grant cuts April 1
Attorney General Phil Weiser sues to stop dismantling of U.S. Department of Education and protect students March 13
Attorney General Phil Weiser joins lawsuit against mass firings (opens new tab) March 6
Attorney General Weiser joins lawsuit against feds to save K-12 teacher preparation grants for Colorado rural schools March 6
Colorado joins lawsuit challenging White House order criminalizing and ending funding for gender-affirming care Feb. 19
Attorney General Phil Weiser sues Trump administration for defunding medical and public health research Feb. 10
Attorney General Phil Weiser joins multistate coalition in suing to stop Elon Musk and DOGEā€™s attacks on Americans info and data Feb. 7
Attorney General Phil Weiser sues to reverse White House freeze on federal funds Jan. 28
Attorney General Phil Weiser challenges unconstitutional executive order ending birthright citizenship Jan. 21


Attorney General Advisories & Remarks

Related events (archive or future listings)

Watch the Replay: Community Impact Hearing Townhall

Protecting Your Rights Against Illegal Federal Action | April 16, 2025 – Denver, CO

Weiser was joined by fellow state attorneys generalā€”Anne Lopez (HI), Aaron Ford (NV), and Nick Brown (WA)ā€”for a powerful discussion on how state leaders are pushing back against illegal federal overreach. They shared how theyā€™re working to uphold civil rights, protect communities, and ensure every voice is heard. Catch up now and hear firsthand how state leadership is protecting your rights and shaping the future.