Weiser, Colorado AG’s office has filed or joined 20 lawsuits challenging Trump executive actions

Colorado Attorney General Phil Weiser, who is running for governor in 2026, at a Denver roundtable in 2023 (Lindsey Toomer/Colorado Newsline).

Since President Donald Trump took office, Colorado has joined numerous legal actions challenging executive orders and other policies implemented by the new administration. 

Colorado Attorney General Phil Weiser, a Democrat who is running for Colorado governor in 2026, joined 20 lawsuits against the Trump administration so far and filed several amicus briefs in other legal challenges.

Here is a look at the legal measures Colorado has taken against Trump administration policies since the Jan. 20 inauguration.

Birthright citizenship

On Inauguration Day, Trump issued an executive order to end birthright citizenship in the U.S. 

Weiser and a coalition of other attorneys general filed a lawsuit in the U.S. District Court of Massachusetts on Jan. 21 claiming that action violates 14th Amendment and a section of the Immigration and Nationality Act. The suit seeks to invalidate the executive order and stop any attempts to implement it. 

Section 1 of the 14th Amendment, ratified in 1868, reads, “All persons born or naturalized in the United States, and subject to the jurisdiction thereof, are citizens of the United States and of the State wherein they reside.”

“The idea that a president could override the Constitution with the stroke of a pen is a flagrant assault on the rule of law and our constitutional republic,” Weiser said in a statement. 

Another group of states filed a similar lawsuit, and several immigration and civil rights advocacy groups filed a suit challenging the order as well. 

Multiple judges have blocked the Trump administration from enforcing the executive order until the cases challenging it are resolved.

Freeze on federal funds

The Office of Management and Budget issued a sweeping freeze on all federal funding on Jan. 27. 

Colorado and over 20 other states filed a lawsuit in the U.S. District Court of Rhode Island on Jan. 28 arguing the freeze is unlawful. 

Weiser said in a statement that the action violates the separation of powers and is “causing massive harm” in Colorado, affecting health care, education and public safety. 

A Rhode Island judge issued a preliminary injunction in states included in the lawsuit on March 6, and wrote in a 45-page decision that the proposed freeze undermined “the distinct constitutional roles of each branch of our government.”. 

A separate preliminary injunction a Washington, D.C., judge entered in late February applies nationwide.

Tesla’s Elon Musk of the Department of Government Efficiency (DOGE).

DOGE data privacy

Weiser joined a coalition of attorneys general in filing a lawsuit in the U.S. District Court for the Southern District of New York on Feb. 7 aiming to stop Elon Musk and the Department of Government Efficiency, or DOGE, from accessing private taxpayer data. 

The suit followed news that a team of DOGE employees accessed sensitive Department of Treasury data through its payment infrastructure. 

The attorneys general said Trump and Treasury Secretary Scott Bessent illegally provided DOGE access to the Department of Treasury’s central payment system and “Americans’ most sensitive personal information, including bank account details and Social Security numbers.”

“The sharing of this sensitive information, reportedly without safeguards on who is receiving access or how they are using this information, risks Coloradans’ privacy, threatens to undermine critical governmental programs, and is taking place without any legal justification,” Weiser said in a statement. 

The lawsuit seeks an injunction prohibiting expanded access to Treasury Department systems as well as a declaration that the administration’s actions were unlawful and unconstitutional.

A New York judge extended a temporary order on Feb. 14 blocking DOGE from accessing Department of Treasury systems. 

In a separate case filed by another group of Democratic attorneys general, a judge in Washington, D.C., ordered that a restraining order prohibiting DOGE from accessing federal agency data is not warranted.

Defunding medical research

The National Institutes of Health announced on Feb. 7 it would no longer pay research universities and medical schools a previously negotiated percentage for indirect costs. Weiser and 21 other attorneys general filed suit on Feb. 10 alleging those cuts were unlawful. 

Filed in the U.S. District Court of Massachusetts, the suit says the Trump administration’s proposed unilateral 15% reimbursement rate would lead to an inability to facilitate biomedical research. The NIH is the primary source of federal funding for medical research. The attorneys general said the cap violates the Administrative Procedures Act. 

According to a news release from Weiser’s office, the move would cut nearly $90 million in research funding across three university campuses in Colorado. 

A Massachusetts judge granted a preliminary injunction on the funding caps in a 76-page decision on March 5 after she extended a temporary block on Feb. 21.  

The Association of American Medical Colleges and the Association of American Universities also filed lawsuits against NIH over the change.

Gender-affirming care

On Feb. 19, Colorado joined Washington, Minnesota and Oregon in a lawsuit challenging a Jan. 28 Trump executive order that threatened the funding of any medical institution that provided gender-affirming care to minors. 

The lawsuit filed in the U.S. District Court for the Western District of Washington intends to block federal agencies from enforcing the executive order, which also threatens criminal charges against medical providers who provide gender-affirming care. It argues the executive order violates the equal protection guaranteed by the 5th Amendment by singling out transgender individuals for mistreatment and discrimination.

Colorado hospitals that provided gender-affirming care to minors abruptly canceled scheduled appointments for transgender children, citing the order and the potential consequences for their funding. 

A federal judge temporarily blocked the order and said it “blatantly discriminated against trans youth,” according to a news release from Weiser’s office.

K-12 teacher training funds

Also on March 6, Weiser joined a lawsuit challenging the U.S. Department of Education’s move to freeze $600 million in grant funding for K-12 teacher training programs. The freeze threatens $2.8 million for a program that prepares teachers to work in rural Colorado communities that have a hard time hiring and retaining teachers. 

Federal funding for the Teacher Quality Partnership and Supporting Effective Educator Development grant programs goes to state universities and other teacher training programs around the country. On Feb. 7, the DOE immediately terminated the distribution of these grants, which were approved by Congress. 

The lawsuit argues the order terminating grants violates the Administrative Procedures Act, and Weiser and the attorneys general from California, Massachusetts, New Jersey, Illinois, Maryland, New York, and Wisconsin sought an order preventing the funds from being frozen. A Massachusetts judge granted a temporary restraining order March 10 reinstating the grant program, arguing he saw “no reasoned explanation articulated” for the program terminations.

Federal worker layoffs

Weiser and a group of 20 attorneys general sued the Trump administration on March 6, claiming mass layoffs of probationary federal employees are illegal and cause irreparable harm to their states.

The lawsuit, filed in the U.S. District Court of Maryland, seeks a ruling that the mass firings are illegal, order that the employees be reinstated, put a stop to similar terminations in the future and identify all of the impacted employees. It says the firing of approximately 24,000 probationary government employees who worked for various federal departments violated laws and regulations regarding “reductions in force.” 

A Maryland judge heard arguments in the case on March 12.

U.S. Department of Education

The U.S. Department of Education announced on March 11 that it would cut about 50% of its workforce. On March 13, Weiser and 20 other attorneys general filed a lawsuit looking to stop the “effective dismantling” of the government agency that supports students and schools across the country. 

The lawsuit, filed in U.S. District Court of Massachusetts, says the cuts to the department’s workforce are illegal and unconstitutional, as the department is an executive agency authorized by Congress. It seeks a court order saying the Trump administration must stop efforts to shut the department down. 

A news release from Weiser’s office says Colorado received over $1.2 billion from the federal government in 2024 for school programs.

Public health grants

Weiser led a lawsuit against the U.S. Department of Health and Human Services and Secretary Robert F. Kennedy Jr. after it abruptly terminated $11 billion in grant funding, citing the end of the COVID-19 pandemic as reason to stop the funding. 

Colorado could lose up to $229 million in grant funding as a result of the cuts. That could affect state public health programs such as immunization distribution, training for local public health agencies on infectious disease, lab services and replacing aging lab equipment. 

The lawsuit asks the U.S. District Court of Rhode Island to stop the grant terminations in the 23 states that filed the suit and Washington, D.C..

Elections executive order

Trump issued an executive order in March that requires proof of citizenship to register to vote and vote, requires all ballots be counted on Election Day, and threatens federal funding for states that don’t comply, among other changes. 

Weiser and 19 other attorneys general asked the U.S. District Court of Massachusetts to declare certain provisions of the order unconstitutional and void. 

The Constitution grants states the right to oversee their own elections, with Congress permitted to regulate certain aspects. 

Voting rights advocates and the Democratic National Committee have filed separate lawsuits challenging the legality of Trump’s order too.

Stalled medical research grants

A lawsuit including Colorado and 15 other states claim the National Institutes of Health under the Trump administration has purposely delayed the review process for medical research grants that should have already been issued.   

The agency has refused to pay for multi-year grants that were approved under previous administrations, citing disagreements over race and gender issues, the suit filed in the U.S. District Court of Massachusetts says. Research institutions received letters alerting them that their grants were canceled in relation to “DEI,” “transgender issues,” or “vaccine hesitancy.” 

Weiser and other Democratic attorneys general on the suit asked the court to issue an injunction requiring the NIH to continue distributing the grants, and declaring the efforts to stall funding distribution unconstitutional.

Dismantling federal agencies

Weiser and 20 other Democratic attorneys general filed a suit in the U.S. District Court of Rhode Island challenging Trump’s executive order attempting to dismantle federal agencies created by Congress. 

While Trump has taken several actions attempting to cut down other federal agencies, the lawsuit is focused on the Institute of Museum and Library Services, the Minority Business Development Agency and the Federal Mediation and Conciliation Service. The order Trump issued on March 14 orders the agencies “to eliminate every one of their programs and components not mandated by statute.” 

“This executive order unconstitutionally overrides Congress’s power to decide how federal funds are spent,” Weiser said in a statement. “By joining this lawsuit, we are standing up for museums like History Colorado, as well as libraries, workers, and minority businesses.”

Tariffs

Weiser announced alongside Colorado Gov. Jared Polis on April 23 that Colorado joined a lawsuit to block Trump’s move to implement tariffs through four executive orders without approval from Congress. 

The lawsuit asks the U.S. Court of International Trade to declare that Trump acted beyond his legal authority and contrary to law when he issued orders implementing tariffs based on the International Emergency Economic Powers Act, which does not grant the president the power to impose tariffs. It also asks the court to enjoin federal agencies from maintaining the tariffs. 

The Federal Reserve projected tariffs Trump has initiated will lead to inflation. 

“Tariffs are awful for Americans and our economy, and it’s important to use every legal tool possible to reduce trade barriers and increase prosperity,” Polis said in a statement.”

DEI in education

On April 27, Weiser joined a coalition challenging the U.S. Department of Education’s threat to withhold funding from agencies that do not comply with the Trump administration’s directive to cease diversity, equity and inclusion initiatives. 

The DOE said state and local education agencies must provide written statements confirming they will comply with the Trump administration’s “new, vague, confusing, and incorrect” interpretation of Title VI of the Civil Rights Act of 1964 in order to receive federal funding. 

Colorado receives about $870 million in congressionally delegated funding annually to support children and their education. 

The lawsuit asks the U.S. District Court of Massachusetts to declare the mandate from the DOE illegal and null and void and prohibit the agency from enforcing it.

Americorps

A lawsuit 24 states including Colorado filed on April 29 challenged the Trump administration’s orders to reduce the AmeriCorps workforce by 90%. 

AmeriCorps is an independent federal agency that supports community service programs throughout the U.S. The lawsuit filed in the U.S. District Court of Maryland says the orders to reduce its workforce have effectively ended AmeriCorps’ ability to function, with 85% of its staff on administrative leave. It asks the court to declare the “decision to dismantle AmeriCorps” unconstitutional for violating the Administrative Procedures Act and stop it from being enforced.

“In an attempt to dismantle the agency, the Trump administration and its DOGE demolition team made abrupt and drastic cuts to staff and volunteers and terminated grants,” Weiser said in a statement. “We are suing to stop this illegal dismantling of AmeriCorps and preserve the spirit of community service in our state and nation.”

A news release from Polis’ office says in 2024, about 1,400 AmeriCorps members volunteered more than 1 million hours at more than 700 sites across Colorado, supporting wildfire mitigation, mental health and education efforts around the state.

RFK and Health and Human Services

Weiser joined a lawsuit on May 5 “to stop the reckless dismantling” of the U.S. Department of Health and Human Services alongside 19 other attorneys general, he said in a statement.

A news release from Weiser’s office says Kennedy and Trump have fired thousands of federal health workers, shut down vital programs and “abandoned states to face mounting health crises without federal support.” The lawsuit says these actions leave the department unable to serve Americans and seeks a court order to reinstate programs and halt further disruptions. 

Kennedy has said he will reduce HHS from 28 agencies to 15 and he already reduced the department’s staff from 85,000 to 65,000. 

The lawsuit, filed in U.S. District Court of Rhode Island, says the Trump administration cannot implement such sweeping changes without congressional approval.

Wind energy

Another May 5 lawsuit Colorado joined argues the Trump administration’s attempt to freeze wind energy development harms the states’ efforts to diversify affordable, renewable energy sources. 

A Trump executive order halted the federal approval process for wind energy projects, so federal agencies have stopped all permitting and approval. The attorneys general said the order violates the Administrative Procedures Act among other federal statutes. 

A news release from Weiser’s office says Colorado relies heavily on wind energy, as wind makes up about 70% of the state’s renewable energy portfolio. 

The lawsuit asks the U.S. District Court of Massachusetts to declare the directive illegal and prevent Trump from further delaying wind energy development.

Electric vehicle infrastructure

Weiser led a lawsuit on May 7 that intends to stop the Trump administration from terminating billions of dollars Congress approved for electric vehicle infrastructure.

The lawsuit challenges a Trump executive order that mandates federal agencies pause funding from the congressionally approved Infrastructure Investment and Jobs Act, also known as the Bipartisan Infrastructure Law. That policy allocated $5 billion for a national program dedicated to facilitating electric vehicle charging infrastructure in states.

Colorado could lose tens of millions of dollars in funding for electric vehicle infrastructure, a news release from Weiser said.

“A bipartisan majority of Congress authorized funding for electric vehicle infrastructure, and President Trump and the Department of Transportation are breaking the law by revoking it,” Weiser said in a statement. “Colorado has already made significant progress in developing the foundation for infrastructure needed for widespread electric vehicle adoption, and the state’s federally approved plans were designed to fill gaps in rural Colorado and other underserved communities.”

The challenge filed in the U.S. District Court for the Western District of Washington in Seattle seeks an order to declare Trump’s actions unlawful and reinstate the funding.

Homeland Security immigration enforcement

Weiser filed a lawsuit on May 13 against the Federal Emergency Management Agency, the U.S. Department of Homeland Security and Secretary Kristi Noem for threatening to withhold funding from states that do not help the federal government enforce immigration law. 

Noem initially ordered federal agencies under DHS, including FEMA, to cease all funding for jurisdictions that do not assist in federal immigration enforcement. She changed that directive to add certification that a jurisdiction will assist in federal immigration enforcement as a condition placed on federal funds. 

Colorado has received over $143 million in disaster relief funding from FEMA since 2017.

The lawsuit filed in U.S. District Court of Rhode Island says attaching immigration enforcement as a condition to receive federal funding is beyond the federal government’s authority and is unconstitutional.

Transportation immigration enforcement

Shortly after DHS implemented immigration enforcement as a condition to receive funding, the U.S. Department of Transportation followed suit. 

Weiser filed another lawsuit on May 13 against DOT and Secretary Sean Duffy after he told grant recipients he intended to require state and local governments to assist in federal immigration enforcement as a condition of receiving funding from the department. That includes funding for highway construction and public transportation maintenance, among other transportation infrastructure needs. 

Colorado receives more than $1 billion annually from DOT for highway, transit, and airport improvements. 

The lawsuit filed in U.S. District Court of Rhode Island says attaching immigration enforcement as a condition to receive federal funding is beyond the federal government’s authority and is unconstitutional.

Support for other legal actions

Weiser and other state attorneys general filed an amicus brief in support of a lawsuit several unions representing federal workers filed challenging Trump’s “Fork in the Road” buyout offer. The unions argue the offer caused widespread confusion among federal employees and sought a temporary restraining order to stop the program. 

Weiser also joined an amicus brief in support of a lawsuit looking to protect the Consumer Financial Protection Bureau. The Trump administration directed the bureau, an independent agency that oversees banks, lenders and credit card companies, to stop all work and not to take on any new cases on Feb. 9. 

Ahead of Trump’s inauguration, a coalition of states including Colorado filed actions defending a decision by the Bureau of Alcohol, Tobacco, Firearms, and Explosives to prohibit a device that allows gun owners the convert a firearm into a military-grade automatic weapon “because federal defendants can no longer be counted on to defend” the prohibition. Weiser also included Colorado in a similar action regarding a bureau rule that expands which gun dealers must conduct a criminal background check for a purchaser and record the transactions.

On March 12, Weiser and 20 other attorneys general filed an amicus brief in support of a law firm Trump targeted with an executive order for “representing clients that he personally does not like,” the brief says. The Seattle-based law firm, Perkins Coie, employs 71 Coloradans at its Denver office.  

Weiser and 20 other attorneys general penned an amicus brief on April 16 in support of of a lawsuit that aims to protect Social Security Administration workers from “erratic management” and “unlawful layoffs” at the hand of DOGE. The brief says workers are concerned about how staffing changes will affect the administration’s ability to function. 

Another amicus brief Weiser joined on April 18 shows support for two commissioners of the Federal Trade Commission who a lawsuit says Trump fired illegally. The FTC is an independent, bipartisan commission that oversees consumer protection efforts, and commissioners cannot be removed without cause under the Federal Trade Commission Act. 

Editor’s note: This story first appeared on Colorado Newsline, which is part of States Newsroom, a nonprofit news network supported by grants and a coalition of donors as a 501c(3) public charity. Colorado Newsline maintains editorial independence. Contact Editor Quentin Young for questions: info@coloradonewsline.com.