You may have assumed that the fight over net neutrality ended when the Federal Communications Commission approved strict new rules for Internet providers in February. In fact, it's far from over.

The next stage of the battle is heating up with people on both sides of the debate gearing up for a war in the courts that could wind up torpedoing the rules and giving Internet providers more power to control the Web.

Opening a new front Wednesday, the wireless and cable industries asked the U.S. Court of Appeals for the District of Columbia Circuit to put a temporary hold on some of the government's open Internet rules until their lawsuit challenging the regulations is resolved. Meanwhile, consumer advocacy organizations are lining up behind the Federal Communications Commission, vowing to help defend the agency's rules from legal assault.

The FCC's new regulations aim to keep Internet providers from blocking, slowing or prioritizing some Web traffic over others. And FCC officials have said they were confident that the rules would withstand court challenges.

But the industry groups say the FCC's rules will create "unrecoverable losses for [Internet] providers" because they allow the agency to declare "open season" on broadband companies. In their petition, the groups say say the rules would lead to new corporate fees and interfere with the private negotiations between businesses over how best to exchange Internet traffic. In their lawsuit, the Internet providers argue that the FCC's net neutrality regulations are an illegal use of power by the federal government.

"Relief is necessary to avoid the serious and substantial harms that service providers and consumers alike will bear," said Michael Powell, president of the National Cable and Telecommunications Association. Joining NCTA in the petition was CTIA — the wireless industry's top trade group — AT&T, and numerous others.

The industry is asking the court to suspend the FCC's decision to police Internet providers under Title II of the Communications Act, the legal tool that was originally written to oversee legacy phone service.

For its part, the FCC said last week in response to another industry request that it wouldn't put the rules on hold.

"We are confident that the court will deny the request for a stay," said FCC spokesperson Kim Hart. "The public interest clearly favors allowing the Open Internet Order to take effect on schedule.”

But if the court grants a stay, that could signal trouble for the FCC. It would be a sign that at least some judges think think the industry's lawsuit may have merit, casting the future of the FCC's net neutrality regulations into doubt. This is the third time the FCC has tried to implement net neutrality; if the industry wins its lawsuit, that would land the FCC back at square one.

In response to the legal challenges facing the FCC, consumer groups have leapt into the fight, too. The advocacy organization Free Press said Wednesday that it wants to help the FCC fight the lawsuit and fend off "the frivolous claims of phone and cable industry lawyers."

"A vast majority of Americans support net neutrality, and millions of people called on the agency to adopt real net neutrality protections," said Free Press policy director Matt Wood. "The public needs a voice on its side as the phone and cable lobby attempts a legal end-run to strip away our rights to connect and communicate."

Free Press's effort to intervene follows the same decision by the advocacy group Public Knowledge last month. And a slew of other supporters, including Netflix, Tumblr, Etsy and Kickstarter, have also moved to intervene. Being a party to the lawsuit means that if the FCC for whatever reason decided not to defend the rules, the consumer groups could keep fighting, according to Harold Feld, senior vice president of Public Knowledge.

The legal maneuverings represent the next stage of a deeply divisive battle over the future of the Web. Analysts have said that judges aren't likely to grant the industry's request for a stay, but nobody knows for sure what will happen. Either way, the court's decision on the stay will be an important bellwether for net neutrality's future.

This is particularly true for Capitol Hill. There, Republicans have been trying to push legislation on net neutrality that would replace the FCC's rules with their own version. Unsurprisingly, Democrats have largely refused to play ball, sensing that they and the FCC currently hold the upper hand. But all that may change if the FCC's fortunes sour in the courts; if it begins to look like the rules are in jeopardy, analysts say, Democrats will become more willing to strike a deal to preserve protections for Internet users.