The NASL isn't going down without a fight after U.S. Soccer denied extending its Division 2 sanctioning into 2018.

Rebuffed in its effort to maintain second-division sanctioning while trying to ensure it could field the required number of teams next year, the North American Soccer League on Tuesday afternoon announced the filing of a federal antitrust suit against the U.S. Soccer Federation that “seeks injunctive relief against the USSF’s conduct regarding its divisional designations.”

The conciliatory, cooperative tone that surrounded the January awarding of provisional D2 sanctioning to both the NASL and competing USL has vanished. The NASL and the Federation, which the former believes “sought to limit competition from the NASL to MLS and USL,” now officially are at odds.

“The USSF left the NASL no choice except to file this lawsuit,” NASL chairman and New York Cosmos owner Rocco Commisso said. “The NASL has taken this step to protect not just the league, but also the game, fans, and everyone with a stake in the future success of professional soccer leagues based in this country.”

Standards implemented by the USSF in 2014 required the NASL to field at least 12 clubs across three time zones in order to maintain its D2 sanction. There are only eight this year, but the NASL was handed a lifeline last winter after losing one team to MLS and two to the USL. Two expansion teams were recruited in California and other discussions were ongoing. But U.S. Soccer’s board believed there hadn’t been sufficient progress established by its mid-August deadline to extend that sanctioning to 2018.

NASL owners met in New York on Friday to talk strategy. There were several options on the table. There were discussions about figuring out a way to get to 12 teams next year and convince the USSF to reconsider. There technically was the possibility that it could operate as an unsanctioned, renegade competition. It could disband, especially if clubs like North Carolina FC, Indy Eleven or FC Edmonton chose to depart. Or, it could fight. It has chosen the latter.

Last-Gasp Meeting to Shape Future of NASL–and U.S. Soccer's Club Landscape

If the NASL is granted the injunction, it theoretically would maintain its D2 status next year. And that might provide an opening to fight against the standards themselves—which govern stadium and market size, owner investment and net worth, facilities and other criteria—along with alleged conspiracy among U.S. Soccer, MLS and the USL, which affiliates to the higher league.

The USL was given 30 days to submit a plan to meet those standards not achieved by certain clubs (such as stadium or field size), but it’s expected the federation will grant D2 status for 2018. The USL also plans to launch a D3 league in 2019.

In its Tuesday statement, the NASL claimed the federation “has violated federal antitrust laws through its anticompetitive ‘Division’ structure that divides men's professional soccer for U.S.-based leagues based on arbitrary criteria that the USSF has manipulated to favor Major League Soccer (MLS), which is the commercial business partner of the USSF.”

The NASL also said U.S. Soccer “now seeks to destroy the NASL by arbitrarily revoking the NASL's 'Division II' status for the upcoming 2018 season.”

Last month, Miami FC owner Riccardo Silva–who along with Commisso represents the ambitious, true-believer wing of the NASL–filed a claim with the Court of Arbitration for Sport in Switzerland asking for the implementation of a promotion and relegation system in the USA. FIFA recognizes CAS rulings but previously has disciplined national federations involved in civil court proceedings. It's unclear whether that precedent might impact the USSF.