The Trump administration on Tuesday sued the University of California, alleging that UCLA is “deliberately indifferent” to antisemitic harassment of Jewish students, marking the government’s third lawsuit against the UC this year and a sharp escalation of federal civil rights pressure on the nation’s largest public research university system.

The 53-page complaint, filed in U.S. District Court for the Central District of California, alleges UCLA violated federal civil rights by tolerating a hostile environment for Jewish and Israeli students after the Oct. 7, 2023, Hamas-led attack on Israel. The attack prompted Israel’s war in Gaza, which drew widespread student protests and pro-Palestinian encampments in the spring, including one at UCLA that was the site of a violent melee the night of April 30, 2024.

The government is asking the court to force UCLA to repay federal grant money going back more than two years — potentially hundreds of millions of dollars — bar it from new federal contracts until it’s deemed in compliance with civil rights law, and install an independent court-appointed monitor that would oversee its civil rights practices. The department is also asking for the court to force reforms to UCLA’s antidiscrimination procedures.

The demands are much narrower than the wide-reaching changes to campus policies and culture the Trump administration sought from UCLA in August 2025, when it unsuccessfully proposed the university pay roughly $1.2 billion to settle allegations of civil rights violations.

The suit centers on the encampment, alleging masked demonstrators “kicked and slapped Jews, beat Jews with sticks, and assaulted Jews with pepper spray.” The Trump administration said UCLA leaders “took no serious action whatsoever” until May 2, 2024, when police cleared the camp.

The legal filing also alleges that campus leaders have failed to protect Jewish and Israeli students up through this year. To make the case, court documents cite rallies held by Students for Justice in Palestine groups, which are banned as formal UCLA organizations but have continued to hold unauthorized protests on campus. The group includes members and supporters who are Jewish.

“Earlier this year, we sued UCLA for subjecting its Jewish and Israeli employees to an antisemitic hostile work environment,” Assistant Atty. Gen. Harmeet Dhillon, who leads the Justice Department’s Civil Rights Division, said in a statement. “Now, the Department of Justice calls UCLA to account for its toleration of the equally appalling hostile educational environment against its Jewish and Israeli students.”

Responding to the suit Tuesday, UCLA Chancellor Julio Frenk said “the suggestion that UCLA has been passive in the face of antisemitism is simply wrong. Combating antisemitism is a moral imperative — one rooted, for me, in personal history that makes indifference unthinkable.” Frenk is a grandchild of Holocaust survivors.

“In the past year alone, we’ve taken numerous concrete actions to combat antisemitism. We recruited an associate vice chancellor for campus and community safety. We reorganized our Civil Rights Office. We appointed a Title VI officer. And we strengthened our policies to protect both free expression and the safety of every member of our community,” Frenk said.

The Justice Department filed its suit the same morning that Frenk gave his first “state of campus” annual address. The chancellor did not mention the court case in his speech. But he said UCLA was focused on combating antisemitism and “all forms of hatred and bigotry.” Frenk said UCLA, during his tenure that began in January of last year, has been focused on replacing “good intentions with specific actions.”

Suit cites UCLA’s antisemitism task force

The suit draws several of its allegations from a 2024 report produced by UCLA’s former Task Force on Antisemitism and Anti-Israeli Bias, which late that fall faulted UCLA for “broad-based perceptions of antisemitic and anti-Israeli bias on campus.”

That group transformed into UCLA’s Initiative to Combat Antisemitism, which produced a report this month saying UCLA has made strides in improving campus culture, including new training and reforms to the civil rights complaint system, while still having more work to do.

In the wake of campus protests in 2024, UCLA also commissioned a task force on anti-Palestinian, anti-Arab and anti-Muslim racism, which found “increased harassment, violence, and targeting” of those groups since 2024 and suggested reforms to policing and protest rules on campus that it said unfairly targeted pro-Palestinian voices. The Justice Department’s lawsuit does not address those concerns.

The new legal filing adds to a growing list of Justice Department actions against UC this year.

In January, the Trump administration joined a lawsuit alleging UCLA’s David Geffen School of Medicine used a “systemically racist approach” to admissions that privileged Black and Latino applicants over white and Asian American ones, in violation of the Equal Protection Clause and the 2023 Supreme Court ruling barring race-based affirmative action.

In February, the Justice Department sued UC alleging UCLA administrators “routinely ignored” and “failed to report” employee complaints of antisemitism, citing what the department called a “severe and pervasive” workplace problem dating to the 2023 onset of the Israel-Hamas war.

The Justice Department has also recently widened its civil rights scrutiny of the state’s medical schools beyond UCLA. In March, the department division opened investigations into whether UC San Diego and Stanford engaged in racial discrimination in medical school admissions, demanding seven years of applicant data and putting hundreds of millions of dollars in federal research funding potentially at risk. Both schools have said they comply with state and federal antidiscrimination laws.

Mars holds a special place in the Solar System. It represents marginal habitability. This means it transitioned from warm and wet and potentially hospitable, to cold and dry and inhospitable.

What can its transition tell us about exoplanet habitability?

New research to be published in the Planetary Science Journal examines the question. It’s titled “Mars as an Exoplanet: Lessons from a Planet at the Edge of Habitability.” The lead author is Stephen Kane, Professor of Planetary Astrophysics in the Earth & Planetary Sciences Dept. at the University of California, Riverside. The research is currently available at arxiv.org.

“Mars is the Solar System’s canonical small, rocky planet that transitioned from early geologic activity and surface liquid water to a cold and arid planet with a thin, cold, CO-dominated atmosphere,” the authors write. “The evolution of Mars, in the context of such planetary parameters as size, mass, atmosphere, insolation flux, magnetosphere, and impact history, harbor important diagnostics regarding the development and sustainability of habitable surface conditions.”

*This figure shows the planetary mass and radius data for confirmed exoplanets that have measurements extracted for both properties, extracted from the NASA Exoplanet Archive on 2025, December 31. The data are color-coded in proportion to the flux received from their host stars. The Solar System terrestrial planets are shown as stars. The shaded region indicates the sub-Earth regime. Image Credit: Kane et al. 2026. PSJ*

Our understanding of the exoplanet population has grown enormously in recent years. In exoplanet surveys, small rocky worlds are common and outnumber larger gas planets. But while we know they exist in large numbers, we lack a detailed understanding of their climates, their volatile budgets, and their long-term potential for habitability. According to the authors, Mars can help us understand its exoplanet cousins.

They point out that though size is a basic property of rocky planets, and a good starting point for understanding them, it doesn’t dictate how a planet evolves. “Venus, Earth, Mars, and even the Moon each underwent distinct volatile, tectonic, and atmospheric trajectories despite sharing the same stellar environment, illustrating that planet size alone does not uniquely determine planetary evolution,” they explain.

In this research, the authors synthesize research into how different aspects of Mars—including volatile delivery and loss, photochemistry, climate evolution, magnetism, and other factors—can help our overall understanding of exoplanets and their processes.

“Exoplanet studies often use Earth properties as standard units of measurements, particularly for those relevant to describing the capabilities of exoplanet detection
methods,” the authors write. Mars has many similar properties to Earth, but its diffferences are what’s important in this work.

*These schematic cross sections of Earth and Mars show the major internal components and atmospheric components to scale. For simplicity, oceanic and continental crust for Earth are not distinguished, nor is the interior structure of Earth’s mantle shown. Image Credit: Kane et al. 2026. PSJ*

First of all, Mars formed differently from Earth. It’s formation was rapid at first, then stalled at a sub-Earth mass. The authors describe it as a “stranded planetary embryo” instead of the result of later giant impacts.

The planet’s mass is important in its evolution, which isn’t surprising. “Mars occupies an important position in comparative planetology, since it is both a geologically rich world with a documented history of surface habitability, and a representative example of how small rocky planets can evolve toward atmospheric loss and climatic decline,” they write.

Mars can serve as a framework for understanding rocky exoplanets. One of the main conclusions is that Mars shows how planetary habitability isn’t a static condition. The authors describe it as “a time-dependent outcome governed by competing processes.”

For example, early Mars was volcanic, and released volatiles built up a thick atmosphere that trapped heat. But as its interior cooled and its dynamo stopped, atmospheric escape led to cooling and eventual loss of habitability. “These coupled processes can define a pathway that may be common for Mars-mass planets,” the authors write.

According to our understanding of Mars, habitability is likely to be fleeting more often than not, and Earth shines as a rare example of long-term habitability. “In
this context, Mars represents the edge of the habitable regime, being large enough to host transiently clement conditions, but small enough that atmospheric retention
and replenishment and long-term climate regulation are not guaranteed,” the authors write.

While Mars-mass planets are widely detected, there are shortcoming in those observations. “Our discussion of exoplanet demographics have shown that, while terrestrial-size planets are abundant, confirmed Mars-mass planets with well-constrained masses and radii remain relatively rare, largely due to detection shortcomings,” the authors write. That will change when the Nancy Grace Roman Telescope and its microlensing survey goes live.

As we discover more Mars-mass planets with well-measured constraints, we’re also developing future telescopes that get better at observing exoplanets. “Direct imaging and thermal emission studies, particularly with next-generation facilities, will ultimately determine whether such planets commonly retain thin CO2 atmospheres, undergo desiccation, or exhibit transient volatile cycles,” the researchers explain.

The key idea is that scientists can use what they learn about Mars to understand these observations. “Mars missions will continue to measure atmospheric escape rates, volatile inventories, and climate feedbacks with a level of detail unattainable for exoplanets, while exoplanet surveys contextualize Mars within a broader statistical population,” the authors write.

The researchers explain that as Mars exploration and exoplanet characterization converge, it will deliver an effective new way to better understand the large numbers of small rocky worlds. Scientists will better understand key properties of exoplanets, like the mass necessary to sustain geological activity like plate tectonics. They’ll also develop a better understanding the stellar environment and how it shapes atmospheric survival, as well as other planetary characteristics that shape habitability.

“Within this framework, Mars provides a fundamental benchmark for evaluating the diversity, evolution, and potential habitability of rocky planets throughout the Galaxy,” the authors conclude.