The Justice Department is suing California to block a recently signed law restoring net neutrality rules that the Federal Communications Commission discarded last year, setting up a high-stakes legal bout between the Trump administration and the nation's most populous state.

The announcement comes immediately on the heels of Democratic California Gov. Jerry Brown’s decision to sign the bill into law. Brown had until midnight on Sunday to approve the measure, which was passed by the state’s legislature in August.

The Justice Department should not have to spend valuable time and resources to file this suit today, but we have a duty to defend the prerogatives of the federal government and protect our Constitutional order,” Attorney General Jeff Sessions said in a statement unveiling the action Sunday. “We will do so with vigor. We are confident that we will prevail in this case —because the facts are on our side.”

Consumer advocacy groups touted the law as offering the strongest internet protections in the country. But the telecommunications industry argued the matter should be left to the federal government and called on Brown to veto the measure.

USTelecom, which represents companies like AT&T and Verizon, on Sunday said the California measure will not "help advance the promise and potential of California’s innovation DNA," calling on Congress to "step up with a national framework for the whole internet ecosystem and resolve this issue once and for all.”

California’s bill also earned the rebuke of the FCC, which moved to repeal the Obama-era internet safeguards last year. Chairman Ajit Pai blasted it as illegal, “radical,” and “anti-consumer” during a speech last month.

On Sunday, Pai praised the DOJ's action, saying he looks "forward to working with my colleagues and the Department of Justice to ensure the Internet remains ‘unfettered by Federal or State regulation,’ as federal law requires, and the domain of engineers, entrepreneurs, and technologists, not lawyers and bureaucrats.”

California Attorney General Xavier Becerra swiftly criticized the DOJ action. Becerra has filed a series of lawsuits against the Trump administration, challenging its actions on immigration policy, among other things. He has also filed a multistate lawsuit challenging the FCC’s net neutrality repeal.

"While the Trump Administration continues to ignore the millions of Americans who voiced strong support for net neutrality rules, California — home to countless start-ups, tech giants and nearly 40 million consumers — will not allow a handful of power brokers to dictate sources for information or the speed at which websites load," he said. "We remain deeply committed to protecting freedom of expression, innovation and fairness."

While a number of states have moved to enact laws to prevent internet providers from slowing or throttling traffic, California's effort stands out due to the bill’s broad scope, the state’s size and its status as home to technology.

The law continued a pattern for Trump-era California: When the White House goes one way, America’s largest state does the opposite.

As the administration fulfilled a campaign vow by cracking down on illegal immigration, California passed a so-called sanctuary law shielding immigrants from federal authorities. While the federal government has diluted or walked back Obama-era environmental rules, California has passed laws to block offshore oil drilling and derive all its electricity from clean sources. As soon as the FCC voted to dissolve federal net neutrality rules, California officials vowed to enact their own.

California's action stands in contrast to Republican-controlled Congress, where a resolution to overrule the FCC has passed the Senate but is unlikely to clear the House.

Sensing a winning political issue, congressional Democrats have spotlighted the state's net neutrality efforts. House Minority Leader Nancy Pelosi had urged Brown to sign the bill and predicted it could lend critical leverage to federal lawmakers.

“Once we establish California as a model of a state taking action, other states may follow, and then I think you may see some of corporate America say ‘OK, let’s have a federal law, because we don’t want to have to do different things in different states,’” Pelosi said at a recent press conference in San Francisco.

In Sacramento, internet service providers sought to stymie the bill by warning that California’s proposed rules would exceed the previous FCC standard, hamstring companies, and undermine California’s status as an incubator for new technologies. Telecom companies and industry groups have spent more than $6 million lobbying Sacramento over the last few years.

We have been and need to continue to be the leader in encouraging innovation, creativity and investment, not the state that brags it has the most prescriptive internet regulation and damaging internet regulation in the country if not the world,” California Technology Industry Association lobbyist Stephen Carlson told lawmakers, warning that “alarmist speculation” will “curb if not stifle the next generation of digital innovation.”

Despite that criticism, the bill ended up passing by a comfortable margin. It garnered the support of organized labor, whose politically influential representatives framed an open internet as a critical tool allowing workers to band together.

As the debate advanced toward a critical vote, a California fire chief lobbed in the claim that Verizon had throttled his department’s data, hobbling its efforts to respond to a catastrophic wildfire. While Verizon swiftly blamed a customer service lapse that it said was unrelated to net neutrality issues, the episode offered lawmakers and advocates a cautionary tale about the risks of restricting internet use.

Becerra warned in response that “open access to online content without interference or manipulation by providers” can “mean the difference between life/death.”

California's two Democratic senators, Kamala Harris and Dianne Feinstein, expressed “alarm” about the incident in letters to the FCC and to major internet service providers, demanding more information and pressing telecom giants to ensure that first responders are not subjected to data caps or throttling.