Speaking before a crowd of law enforcement officials in a state he had just accused of violating the Constitution, Attorney General Jeff Sessions excoriated California and some of its state and local leaders Wednesday for passing laws and taking actions that he said obstruct immigration enforcement and put officers in danger.

In an unusually strident speech that emphasized the supremacy of the federal government by referencing Abraham Lincoln and secession, Sessions said California’s actions “directly and adversely impact the work of our federal officers” and “undermine the duly-established immigration law in America.”

He took particular aim at Oakland Mayor Libby Schaaf (D) for warning constituents last month about an impending raid by Immigration and Customs Enforcement agents, alleging that her comments prevented authorities from making 800 arrests. And he said he plans to use the full might of the federal government to bring her state in line.

“California, absolutely, appears to me, is using every power it has — powers it doesn’t have — to frustrate federal law enforcement,” Sessions said. “So you can be sure I’m going to use every power I have to stop them.”

The comments at the California Peace Officers Association’s annual gathering in Sacramento came a day after the Justice Department sued the state of California, alleging that three recently passed laws that benefit undocumented immigrants are unconstitutional. The lawsuit, which seeks to block the laws, represents a major escalation of the attorney general’s crackdown on “sanctuary” jurisdictions, and it drew swift criticism from state leaders, who insisted that their laws would pass legal muster.

Sessions’s comments also sharpen a burgeoning feud between the U.S. government and its most populous — and perhaps most anti-Trump — state. Soon after he was finished speaking, the Trump campaign messaged supporters about the issue in an email with the subject line, “California vs. THE LAW.”

“Americans across the country now can see that Democrats have officially become the party of obstruction, lawlessness, government shutdowns, and of putting illegal immigrants before American citizens,” the email said.

Those inside the Sawyer Hotel clapped loudly when Sessions finished speaking, though the view among those in law enforcement is nuanced.

John McGinness, a 60-year-old former Sacramento County sheriff who attended the conference, said he was optimistic that the legal fight between the state and federal government would ultimately resolve confusion related to immigration policy.

“This represents the potential for some clarification that is desperately needed,” McGinness said. “It’s like a child getting diametrically opposing directives from his parents. What is the child to do?”

California State Sheriffs’ Association President Bill Brown, whose group opposed one of the bills over which the Justice Department is suing, said in a statement, “Sheriffs are caught in the middle of this challenging issue.”

“Sheriffs do not wish to act as immigration police, nor are they, and we protect EVERYONE in our communities regardless of immigration status,” Brown said. “That said, we need to continue to cooperate with our law enforcement partners — especially as it relates to the release of offenders from our jails — to ensure that those who victimize our communities are not given unnecessary opportunities to do more harm.”

Outside the hotel, the mood was more combative. A few hundred demonstrators rallied in Sacramento’s downtown core, listening to speeches and then pouring into the street — forcing police on horseback to divert traffic.

Tre Borden, 33, a Sacramento art producer and consultant who was among those protesting, said those gathered were “motivated and angry” that Sessions came to the city. “We’re here to show that immigrants are vital to our community,” he said.

Sacramento City Councilman Eric Guerra, who came to California illegally as a child from Jerahuaro, Mexico, and was among those to speak at the demonstration, said, “This is a full-frontal disregard for our belief as an inclusionary city and state that recognizes diversity.”

State leaders, meanwhile, girded for battle. In fiery remarks after Sessions’s speech, Gov. Jerry Brown (D) said that “the Trump administration is full of liars” and called on Sessions to apologize for “bringing the mendacity of Washington to California.”

He said the Justice Department’s lawsuit was a “political stunt” and said it was ironic that Sessions, who is from Alabama, talked about secession. He suggested that the attorney general might be trying to get back into the good graces of President Trump, who has publicly voiced displeasure about him.

“It really demeans the high office to which he has been appointed,” Brown said, adding later that Sessions was “initiating a reign of terror.”

In an interview with Fox News that was set to air Wednesday night, Sessions praised the president effusively, saying, “I think President Trump moves the ball. He can get things done that I’m not sure any other person in America could get done,” according to an excerpt distributed by the network.

Sessions’s speech touched on themes familiar to those who have followed his career, in the Senate and as attorney general — rising violent crime, respect for law enforcement, and illegal immigration. But his remarks were notable for their aggressiveness.

At one point, after referencing the “wide variety of political opinions out there on immigration” and the law already on the books, he said: “There is no nullification. There is no secession. Federal law is the supreme law of the land. I would invite any doubters to go to Gettysburg, or to the tombstones of John C. Calhoun and Abraham Lincoln. This matter has been settled.”

The Justice Department’s lawsuit takes aim at three California laws that prohibit private employers from giving immigration officials access to workplaces or documents for enforcement without a court order; create a state inspection system for immigration detention facilities; and limit what state and local law enforcement authorities can communicate about some suspects.

Sessions noted that — outside the context of immigration — they might be viewed differently.

“Just imagine if a state passed a law forbidding employers from cooperating with OSHA in ensuring workplace safety,” he said, referring to the Occupational Safety and Health Administration. “Or the Environmental Protection Agency for looking after polluters. Would you pass a law to do that?”

To Schaaf in particular, whose warning he said disrupted an ICE raid, Sessions said: “How dare you? How dare you needlessly endanger the lives of our law enforcement officers to promote a radical open-borders agenda?”

In a statement in response, Schaaf said: “How dare you vilify members of our community by trying to frighten the American public into thinking that all undocumented residents are dangerous criminals. . . . How dare you distract the American people from a failed immigration system that tears apart decent families and forces the workers that our economy depends on to harvest our crops, deliver our services, and build our cities to live in fear and work under oppressed conditions. How dare you distort the reality about declining violent crime rates in a diverse, sanctuary city like Oakland to advance a racist agenda.

Several “sanctuary” jurisdictions have sued the administration over its attempt to keep federal grant money from them, and the early skirmishes have gone against the Justice Department. A federal judge in San Francisco blocked Trump’s executive order on sanctuary jurisdictions, a federal judge in Chicago ruled that Sessions had exceeded his authority in imposing new, immigration-related conditions on grants, and a judge in Philadelphia declared that the Justice Department could not withhold money from that city, because it was in compliance with immigration law.

Sessions has threatened to subpoena 23 jurisdictions that officials suspect might not be complying with immigration law, and a senior Justice Department official said it is possible that the department will sue places other than California. That state, though, has drawn the particular ire of the administration, and a senior Justice Department official said its laws stood out as violating the Constitution.

California officials rejected that claim. State Attorney General Xavier Becerra (D), who talks proudly of his 28 lawsuits against the administration, said the Justice Department was mischaracterizing the laws it was challenging — laws he said were “fully constitutional.”

California State Senate President Kevin de León (D) said early Wednesday: “If Jeff Sessions is suing California because we refused to help the Trump administration round up honest, hard-working families, then I say bring it. Based on the Justice Department’s track record in court, I like our odds.”

Sessions’s decision to sue the state not only sparks an immediate legal battle but also could have political repercussions in several statewide races.

De León, who is term limited as state Senate president, is challenging U.S. Sen. Dianne Feinstein (D) in a contest that sets up generational, ethnic and ideological contrasts. Neither candidate earned the formal endorsement of the California Democratic Party last month, but de León bested Feinstein in the raw vote tally of Democratic convention delegates.

De León was scheduled to be in Washington on Wednesday and Thursday for fundraisers and other political meetings but canceled the trip when his office learned of Sessions’s plans.

Feinstein said in a statement Wednesday that the Trump administration “continues to attack California in an attempt to score points with the president’s political base. These attacks are unacceptable and will not be tolerated.”

“California should not be punished for trying to shield immigrants from deportation and keep families together,” Feinstein said.

In an interview Wednesday, Sen. Kamala D. Harris (D-Calif.) said she was struck that Sessions, who has faced questions about his personal statements and actions on civil rights, would openly discuss secession.

“I think that Jeff Sessions in particular should understand that when he starts evoking Civil War comparisons it’s going to be interpreted as highly offensive, and if I were him, I’d avoid making Civil War comparisons,” she said.

The lawsuit and showdown with Sessions also could be a boon for Becerra, a former congressman who became the state’s top law enforcement official last year when Harris became California’s other U.S. senator. He has spent much of the past year filing legal challenges to the Trump administration’s actions on immigration, health care and environmental policy, and this year he will face his first statewide election to win the attorney general’s job outright. The contrast between him and Sessions, both former lawmakers, is notable.

Sessions was a fringe player on immigration in the U.S. Senate for 20 years who pushed for tougher enforcement and voiced concern that the fast-growing “sanctuary city” movement was allowing immigrants who committed serious crimes to remain in the United States. Becerra, whose mother was from Mexico and whose U.S.-born father grew up there, worked on an unsuccessful bipartisan effort to grant legal status to the 11 million undocumented immigrants in the United States — including about 2.3 million in California.

The Justice Department suing states is unusual but not unheard of. It did so several times during the Obama administration, including a suit against Arizona over a law there that cracked down on illegal immigration.

Zapotosky and O’Keefe reported from Washington. Maria Sacchetti in Washington contributed to this report.