During the four years that Donald Trump was president the first time, California sued him about every 12 days on average.

Now that he’s returning to office, Democratic state leaders are preparing potential new lawsuits.

State Attorney General Rob Bonta has been developing plans to defend California policies since the summer, when polls showed a good chance that Trump would win the election. Bonta has said his team has preemptively written briefs on a variety of issues in preparation of what’s to come.

“During the previous Trump administration, California (Department of Justice) fought hard against Trump’s rollbacks and unlawful policies that infringed on Californians’ rights…and would do so again if need be,” the attorney general’s office said in an unsigned email response before the election.

California sued the Trump administration 123 times and scored major victories. Among them: California defended the state’s clean air rules, preserved the Deferred Action for Childhood Arrivals program (DACA) that benefits undocumented people who came to the United States as children, and protected the Affordable Care Act.

Those issues — the environment, immigration and health care — could once again be the main battle lines in the lawsuits that are expected to be waged between California’s Democratic administration and Trump’s White House.

Gov. Gavin Newsom foreshadowed potential disputes in a statement Wednesday.

“California will seek to work with the incoming president — but let there be no mistake, we intend to stand with states across our nation to defend our Constitution and uphold the rule of law,” he said. “Federalism is the cornerstone of our democracy. It’s the United STATES of America.”

This time, some experts anticipate that Trump will bring forward a more methodical approach to policy.

They point to Project 2025, a 900-page document by the conservative think tank the Heritage Foundation that lays out a conservative agenda. While Trump tried to distance himself from the blueprint during his campaign, former members of his administration contributed to the report. There is also some overlap between what he’s proposed and what’s outlined in the document, such as mass deportations and overhauling the Justice Department.

Choosing battles in a second Trump term

In his victory speech, Trump signaled policy objectives that would likely conflict with California’s goals, such as expanding oil production and turning the nation’s public health agencies over to vaccine skeptic Robert F. Kennedy Jr. — although in what capacity is still unclear.

“He’s going to help make America healthy again,” Trump said about Kennedy during his speech. “I just said: ‘But, Bobby, leave the oil to me.

“‘Bobby, stay away from the liquid gold. Other than that, go have a good time.’”

While Democratic leaders vow to uphold their values, they may be more careful in choosing their battles this time around, said Matt Lesenyie, a political science professor at Cal State Long Beach.

“Some of the legal challenges are substantive, like we want to regulate greenhouse gasses. Other ones may be more symbolic, and that’s not to trivialize cultural or gender identity, but one thing that has been clear, at least to me in this Trump win, is that those cultural issues are motivating his voters,” he said.

Because it is a large state, California also has power to negotiate with the federal government.

“Faced with near-total Republican control of the federal government, Sacramento may think the state does better by negotiating,” said David A. Carrillo, executive director of Berkeley Law’s California Constitution Center. “That affects whether California’s strategy is to fight on all fronts, or to focus on leveraging its size and market power in making its own domestic and international agreements — call it soft secession.”

Likely disputes over abortion, health care

By most accounts, health care policies are expected to be contested again.

In his first term, Trump’s efforts to repeal the Affordable Care Act failed, but he did slash some provisions of the landmark health law.

He also influenced the reversal of Roe v. Wade, the 1973 ruling that protected abortion rights, by appointing three conservative Supreme Court justices.

In 2019 the Trump administration also blocked clinics and providers that offer or refer patients to abortion services from receiving federal family planning dollars. California sued. The Biden administration later reversed Trump’s rule. Any similar restrictions on abortion would certainly prompt California to respond with litigation again.

Carrillo anticipates that the Trump administration might move to restrict mifepristone, one of the medications used to induce abortion, by using a 19th Century law known as the Comstock Act.

“One fight California probably can’t avoid is abortion, specifically access to mifepristone,” Carrillo said. “For example, the federal Comstock Act in general bans sending something for ‘abortion-causing purposes’ in the mail.

“Expect a major legal battle if federal prosecutors start enforcing that to prevent interstate shipping of medical abortion drugs or contraceptives,” he said.

Others say they also expect a fight from states if Trump attempts to make drastic cuts to the Medicaid program. About 14.7 million low-income Californians rely on Medicaid for health coverage. The program is also known as Medi-Cal in California.

Project 2025, for example, proposes to cap what the federal government pays for the Medicaid program, which is funded by both the feds and the states. This means that states would receive a fixed amount regardless of their costs. In the health policy world this is referred to as “block grants” or “per capita caps.”

“So that’s a big cut, a big cost shift to states, and states would have no choice but to either raise taxes substantially or far more likely, shrink their Medicaid programs to a great degree, which means more uninsured, more people go without needed care,” said Edwin Park, a research professor at the Georgetown University McCourt School of Public Policy.

Park says one key difference between a second Trump administration and the first is that Trump and his team could have a clearer vision of what they want to do with health care programs this time around. That includes the potential for things like imposing work requirements to qualify for Medi-Cal or slashing aid in Obamacare marketplaces, making it less affordable to sign up.

Ana B. Ibarra and Nigel Duara are reporters with CalMatters.