Within minutes of the U.S. Federal Communications Commission vote to roll back Obama-era net neutrality regulations, threats of lawsuits to block the move rolled in.

"Allowing internet service providers to discriminate based on content undermines a free and open Internet," Washington State Attorney General Bob Ferguson said in a statement announcing the intention to file challenges along with colleagues from other states.

Democratic Attorneys General Eric Schneiderman, of New York, and Lisa Madigan, of Illinois, also announced plans to sue, as did Free Press, an activism group that helped organized the opposition to the FCC’s party-line vote to strike down open-internet policies. They are likely to be joined by others in coming weeks.

But the lawsuits face long odds of succeeding because courts generally defer to the expertise of federal agencies, said James Speta, a Northwestern University law professor who favored the net neutrality rules.

"The agency is entitled to deference, so it will be a long hill to climb," Speta said.

The Republican-led FCC voted 3-to-2 on Thursday to remove Obama-era prohibitions on blocking web traffic, slowing it or demanding payment for faster passage via their networks. Over objections from its Democrats, the FCC gave up most authority over broadband providers such as AT&T Inc. and Comcast Corp. and handed enforcement to other agencies.

Related:As U.S. Unwinds Web Rules, Industry’s Voice Echoes the Loudest

“It is time for us to restore internet freedom,” said FCC Chairman Ajit Pai, who was chosen by President Donald Trump to lead the agency, and who dissented when the FCC adopted the rules under Democratic leadership in 2015. “We are restoring the light-touch framework that has governed the internet for most of its existence.”

Eliminating the regulations frees broadband providers to begin charging websites for smooth passage over their networks. Critics said that threatens to pose barriers for smaller companies and startups, which can’t afford fees that established web companies may pay to broadband providers, or won’t have the heft to brush aside demands for payment. Broadband providers said they have no plans for anti-competitive “fast lanes,” since consumers demand unfettered web access.

More: Open-Internet Rules Fight Seen Raging Beyond FCC Rollback

The new rules will take effect after a White House review expected to take a few months.

Free Press, the activist group, announced it planned "to sue the FCC on the basis of its broke process, deeply flawed legal reasoning, willful rejection of evidence that contradicts its preordained conclusions, and absolute disregard for public input."

Ferguson, a Democrat whose office was at the forefront of the fight against Trump administration’s attempt to ban travel from several majority-Muslim countries, said "We are 5-0 against the Trump Administration because they often fail to follow the law when taking executive action."

He said he would mount a challenge based on the Administrative Procedures Act, a law designed to prevent an incoming administration from overturning its predecessor’s actions without showing a need or change in circumstance.

Why Trump’s FCC Tossed Obama’s Net Neutrality Rules: QuickTake

"There is a strong legal argument that with this action, the federal government violated the Administrative Procedure Act — again," Ferguson said in a statement. "We will be filing a petition for review in the coming days."

At a news conference after the vote, Pai defended the legality of the vote.

"There’s no question that what we did was lawful,” Pai said. “I’m very confident that our decision will be upheld.”

Pai may benefit from a legal doctrine that gives regulatory agencies the benefit of the doubt in legal questions. The so-called Chevron deference was named after the 1984 U.S. Supreme Court case that birthed the concept.

But the case may not even come down to that. In order to get the FCC’s decision overturned, those suing would have to show "not only that net neutrality might be a good idea, but that it is actually somehow required by the law," George Mason University law professor Ilya Somin said in an email.

Killing Obama’s Rules? Congress Has an Act for That: QuickTake

"If so, that would mean that the FCC was in violation of the law throughout all the years prior to 2015 when the internet existed, yet the FCC did not require net neutrality," Somin said. "To my knowledge, no one has presented a serious argument that even comes close to proving any such thing."

New York’s Schneiderman said he would sue over irregularities found in some of the 24 million public comments that were filed with the FCC since Pai proposed the rollback. Many of those appeared to be of dubious origin including almost half a million routed through Russia and others that were signed by people who hadn’t actually sent them.

Schneiderman said he would fight the "illegal rollback of net neutrality" and cited "two million fake comments that use the stolen identities of people across the country."

He was part of a group of 18 democratic attorneys general who appealed unsuccessfully to Pai to delay the vote over the irregularities in the comments.

Randolph May, once the commission’s associate general counsel and now president of the Maryland-based Free State Foundation, a free-market think thank, predicted the litigation will ultimately fail. He cited a 2005 U.S. Supreme Court decision affirming the FCC’s authority.

While Pai’s plan expressly barred individual states from enacting their own regulations, there may be a court fight ahead to clarify the fine line between where federal authority ends and a state’s power to protect its citizens begins, said Matthew Schettenhelm, an attorney and government litigation analyst with Bloomberg Intelligence. He said that despite Pai’s effort to avoid a patchwork of local requirements, states aren’t completely sidelined.

Massachusetts Democratic Senator Edward J. Markey said he would mount a two-pronged attack to preserve the rules. Besides supporting legal action, he and other lawmakers said they would introduce a resolution under the Congressional Review Act that allows Congress to overturn some actions of regulatory agencies.

"We will fight the FCC’s decisions in the courts, and we will fight it in the halls of Congress,” Markey said.

    Read more: www.bloomberg.com