Four states' attorneys general have filed suit to prevent the transition of critical internet functions from the US government to non-profit ICANN this Friday.

The lawsuit from Arizona, Texas, Oklahoma and Nevada seeks a temporary restraining order that would prevent the IANA contract from expiring on September 30. (If or when it expires, IANA, which oversees the world's DNS and IP address allocations, will be completely under ICANN control.)

This legal challenge comes the day after an effort to get Congress to block the transition failed.

The lawsuit [PDF] has been filed in Texas and a judge is expected to rule on whether to put a hold on the transition later today. The US Department of Commerce's National Telecommunications and Information Administration (NTIA) has said it will not comment on the matter.

The attorneys general make five main claims:

The contract is US government property and requires explicit Congressional approval before it can be handed over.

The transition would violate the First Amendment.

The NTIA did not follow the correct public comment procedures.

The NTIA does not have the authority to hand over the contract.

The transition does not properly protect the .gov and .mil top-level domains.

As you would expect from a lawsuit lodged by states' top lawyers, the content and explanations within the lawsuit over how the internet works and the role of the NTIA and ICANN is largely accurate – a rarity in this area.

There are significant flaws in the arguments put forward, however.

The critical issue is likely to be what is allowed to happen to the .gov and .mil top-level domains, since this is the issue on which the attorneys general have hitched their right to sue.

The states rely heavily on the use of .gov domain names and argue that following the transition, "the States have no assurance that ICANN will not delete the .gov top-level domain name or otherwise increase costs for the States."

Letters

ICANN has signed an "exchange of letters" with the NTIA over .gov and .mil in which ICANN accepts that it will inform the NTIA of any requests to redelegate four US-government run top-level domains: .mil, .gov, .edu and .us. ICANN also promises that it will not make any changes to those names "without first obtaining express written approval from NTIA."

The lawsuit claims this exchange of letters is insufficient, arguing that they are "non-binding and lack the certainty of a legal contract." When asked about the fact that the NTIA did not sign an actual contract with ICANN over the names at a recent Senate hearing, assistant commerce secretary Larry Strickling explained that the decision reached by the Department of Commerce was that a contract would confer a sense of ownership over the names to ICANN. The US government's position is that it owns the top-level domains and ICANN is simply administrating them.

This approach is in fact the norm with the domain name system: most of the top-level domains that are not under contract with ICANN – typically country-code names like the United Kingdom's .uk or Germany's .de – have a similar "exchange of letters" that recognizes ICANN as authorized to make changes, but does not grant the organization a legal claim over the top-level domain.

That compromise was arrived at following several years where ICANN attempted to force countries to sign a contract with it and they refused.

The lawsuit argues that there's nothing to stop ICANN from making changes anyway: "For example, ICANN could eventually delete the .gov top-level domain name or transfer it to some other entity, cutting off communications between the States and their citizens and forcing the States to use ordinary top-level domain names (such as .com) to try to communicate with their citizens."

ICANN would in fact never do such a thing, because it would immediately undermine its authority and almost certainly result in the collapse of the single interoperable internet.

There is also a peculiar irony that the lawsuit makes the exact same argument that other countries have been making for why the US government should not be in charge of the IANA contract: because it could, theoretically, hand over control of a top-level domain to someone else. In reality, it would never happen.

Despite that, it is far from clear that a Texas judge will accept the unusual way the internet works and refuse a temporary restraining order (TRO), rather than approve it and let the argument play itself out through the legal process.