The Department of Justice has sued the state of California after Governor Jerry Brown signed California’s first net neutrality bill, SB822, into law Sunday evening. It’s the start of a new chapter in the never-ending battle to keep the internet healthy and competitive in the face of growing telecom monopoly power.

Like the FCC’s dismantled 2015 net neutrality rules, SB822 prohibits ISPs from unfairly throttling or blocking websites and services that compete with an ISP’s own offerings.

The bill also places meaningful restrictions on behaviors like “zero rating,” a practice that lets deep-pocketed companies buy an unfair advantage by exempting their content from arbitrary broadband usage caps and overage fees. SB822 also prohibits the kind of anti-competitive interconnection shenanigans that slowed customer Netflix streams back in 2014.

"While the Trump administration does everything in its power to undermine our democracy, we in California will continue to do what’s right for our residents," bill author and California State Senator Scott Wiener said in a statement. Within hours of Brown signing SB822, the Trump administration Department of Justice issued a statement stating that it would be suing California over the new law , claiming it “unlawfully imposes burdens on the Federal Government’s deregulatory approach to the Internet.”

SB822 had already faced a tumultuous path in the run up to Brown’s signing, with entrenched broadband providers like AT&T and Comcast attempting to hamstring the effort at every turn. Procedural gamesmanship back in June nearly stripped away many of the bill’s most important components. ISP-linked groups also conducted extremely misleading robocalls aimed at senior citizens in further efforts to hamstring the proposal. Public backlash to those efforts forced the California Assembly and Senate to approve a fully-intact version of the bill in late August. ISP lobbyists met with Brown in early September urging him to veto the measure.

“The pressure from the big broadband providers to kill or water down the bill was enormous,” said former FCC lawyer Gigi Sohn in a statement to Motherboard. “What happened in California should send a message to other states and to Congress―the American people want the open Internet protected, and they will fight extremely hard until they achieve that goal,” Sohn said.

Groups like the Electronic Frontier Foundation have called California’s net neutrality bill the “gold standard” for other states looking to pass their own laws. More than half the states in the country are considering either net neutrality laws, or executive orders prohibiting states from doing business with ISPs that behave anti-competitively. Former Verizon lawyer turned FCC boss Ajit Pai has called California’s bill both “illegal” and “radical.” ISPs have also threatened to “aggressively” sue states that pass their own net neutrality rules, though have yet to carry through on those threats. Given the Department of Justice’s lawsuit, they may not need to lift a finger.

However, such lawsuits may have a steep, uphill climb. In part because the FCC has ironically undermined its own authority to tell states what to do. At ISP lobbyist behest, the FCC included language in its net neutrality repeal attempting to “pre-empt” (read: ban) states from protecting broadband consumers in the wake of federal apathy. But legal experts like Stanford Law Professor Barbara van Schewick have argued that the FCC eliminated its right to tell states what to do when it killed net neutrality last fall.

“An agency that has no power to regulate has no power to preempt the states, according to case law,” van Schewick said in a statement provided to Motherboard. “When the FCC repealed the 2015 Open Internet Order, it said it had no power to regulate broadband internet access providers,” van Schewick added. “That means the FCC cannot prevent the states from adopting net neutrality protections because the FCC’s repeal order removed its authority to adopt such protections.” Courts have so far agreed. Charter Spectrum, the nation’s second-largest cable provider, has tried to use the FCC’s pre-emption language to tap dance around a lawsuit in New York State over terrible service and slow speeds. But the courts have so far rejected Charter’s arguments, stating that states still have the right to rein in ISP “fraud, deception, and false advertising.”

Such efforts face an uphill public relations battle given the broad, bipartisan support net neutrality continues to enjoy. 22 states have already sued the government for ignoring the will of the public on net neutrality, with opening arguments for that case expected sometime in the next few months.