RFC 2146 - U.S. Government Internet Domain Names May 1997: "The .GOV domain is delegated from the root authority to the US Federal Networking Council."
RFC 1956 - Registration in the MIL Domain June 1996: "The ".MIL" domain is delegated from the root authority to the US Department of Defense (DoD). Only US military services, unified or specified commands, and operating agencies of the DoD which do not report through military service chains can be registered as a second level domain under the ".MIL" domain. All other DoD organizations will register through their respective second level domain administrators using the registration procedures established by those offices. The ".MIL" domain is administered by the DoD Network Information Center (NIC)."
The U.S. Department of Commerce, National Telecommunications and Information Administration (NTIA) administers TLDs .EDU and .US.
Note: at present the "root authority" is the U.S. government (U.S. Dept. of Commerce's NTIA). It is now clear that since at least March, 2014, NTIA has wanted to cede its "root authority" to ICANN, a California corporation incorporated on September 30, 1998, which first entered into an IANA Fuctions Contract with NTIA on February 9, 2000 (pdf), according to NTIA's IANA Functions Contract web page.
U.S. Senator Ted Cruz and others in Congress have requested NTIA and the Obama administration to certify that they have secured "sole ownership" of the top-level domain names (TLDs) used by the U.S. government and the U.S. military, specifically, .GOV and .MIL, before any "IANA stewardship transition" occurs.
Form Over Substance:
Presumably in response to the requests of Senator Cruz and others in Congress, Larry Strickling of NTIA, and Goran Marby, President & CEO of ICANN, have traded letters (embedded below), signifying nothing but unenforceable promises that ICANN would notify NTIA of any re-delegation requests for gTLDs .GOV, .MIL, .EDU and ccTLD .US, in the future, and would obtain NTIA approval before taking action on any such re-delegation. Does anyone really think this will satisfy Ted Cruz et al in Congress, particularly in regard to .MIL and .GOV?
Neither Strickling nor Marby cite any binding authority to enforce these promises in the future nor are there any ICANN gTLD registry agreements with such terms to back this up for gTLDs .GOV, .MIL, or .EDU.
As previously remarked on Domain Mondo:
"One easy solution to the above quandary, which most .COM domain name registrants would favor, would be to reclassify the legacy gTLDs (per RFC 1591) .COM, .NET, .ORG, .EDU, .GOV, .MIL as ccTLDs assigned to the U.S. (which historically, in practice (pdf), they always have been), with a mutual declaration by all parties, including the respective registry operators, U.S. government, and ICANN, that .COM, .NET, and .ORG will remain, in perpetuity, open ccTLDs for registration and use by the entire global internet community. In addition, the only other "legacy gTLD" per RFC 1591, .INT, should be assigned to the International Telecommunication Union (ITU) [domain name: itu.int], an international UN agency, for TLD operation and administration, a role which ITU has been ready, willing and able to take on since at least 2003. ITU was involved in the founding of ICANN in 1998 and participates in ICANN's Governmental Advisory Committee (GAC). Current registry operator of .INT is IANA, a department of ICANN, which is a blatant conflict of interest."
ICANN letter (highlighting added):
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