Registrants in the usTLD must be either:
1.A natural person (i) who is a United States citizen, (ii) who is a permanent resident of the United States of America or any of its possessions or territories, or (iii) whose primary place of domicile is in the United States of America or any of its possessions [Nexus Category 1],
2.A United States entity or organization that is (i) incorporated within one of the fifty (50) U.S. states, the District of Columbia, or any of the United States possessions or territories, or (ii) organized or otherwise constituted under the laws of a state of the United States of America, the District of Columbia or any of its possessions or territories (including a federal, state, or local government of the United States or a political subdivision thereof, and non-commercial organizations based in the United States) [Nexus Category 2], or
3.A foreign entity or organization that has a bona fide presence in the United States of America or any of its possessions or territories [Nexus Category 3].
Prospective Registrants will certify that they have a โbona fide presence in the United Statesโ on the basis of real and substantial lawful connections with, or lawful activities in, the United States of America. This requirement is intended to ensure that only those individuals or organizations that have a substantive lawful connection to the United States are permitted to register for usTLD domain names.
It shall be a continuing requirement that all usTLD domain name Registrants remain in compliance with Nexus. To implement the Nexus requirement, NeuStar will:
Require that Registrars certify that they enforce the Nexus requirement upon their Registrants, and that Registrars require Registrants to certify tha t they meet the Nexus requirement.
Conduct a scan of selected registration request information.
Conduct โspot checksโ on Registrant information.
Information Collected From Registrants
To register a name, Registrants (through their Registrars) will be required to provide basic registration information to the Registry. The minimum required information is:
The domain name registered;
The IP address and corresponding names of the primary and secondary name servers for the registered name;
The Registrar name and URL or, where appropriate, the identity of the delegated manager under whom the name is registered;
The original creation date and term of the registration;
The name and postal address of the domain name Registrant;
The name, postal address, e-mail address, voice telephone number, and (where available)fax number of the name holder for the name registered;
The name, postal address, e- mail address, voice telephone number, and (where available) fax number of the technical contact for the name registered; and
The name, postal address, e- mail address, voice telephone number, and (where available) fax number of the administrative contact for the name registered.
In addition to the above information, Registrants will be required to provide certain additional Nexus information to their Registrars. Except where it is noted below that a registration will be rejected if information is missing, failure of a registration to satisfy the Nexus requirement will result in the name being placed upon a 30-day hold, during which time the Registrar will be
notified and given the opportunity to correct the information with the Registrant. If no action is taken by the Registrar within the 30-day period, the registration will be cancelled and the name will be returned to โavailableโ status. The registration fee will not be refunded. If, on the other hand, the Registrar is able to demonstrate compliance with the requirement and the information
is corrected, the hold will be released and the name will be registered.
Certification that Registrant satisfies Nexus requirement โ if not completed, then
registration will be rejected;
Basis for compliance (Nexus Category 1, 2, or 3) โ if not completed, then registration will
be rejected
Certification that the listed name servers are located within the United States โ if not
completed, then registration will be rejected
Nexus Category 1
A natural person (i) who is a United States citizen, (ii) who is a permanent resident of the United States of America or any of its possessions or territories, or (iii) whose primary place of domicile is in the United States of America or any of its possessions.
Statement of citizenship or legal permanent residency required. If not completed, registration will be rejected.
Nexus Category 2
A United States entity or organization that is (i) incorporated within one of the fifty (50) U.S. states, the District of Columbia, or any of the United States possessions or territories, or (ii) organized or otherwise constituted under the laws of a state of the United States of America, the District of Columbia or any of its possessions or (including a federal, state, or local government
of the United States, or a political subdivision thereof, and non-commercial organizations based in the United States).
Nexus Category 3
A foreign entity or organization that has a bona fide presence in the United States of America or any of its possessions or territories.
Applicant must state country of citizenship.
Applicant must also (1) regularly engage in lawful activities (sales of goods or services or other business, commercial or non-commercial including not-for-profit activities) in the United States; or (2) maintain an office or other property within the United States.
Category 3 Nexus Certification
Prospective Registrants will certify compliance with Category 3 Nexus based upon substantial lawful contacts with, or lawful activities in, the United States.
Factors that should be considered in determining whether an entity or organization has a bona fide presence in the United States shall include, without limitation, whether such prospective usTLD domain name Registrant:
Regularly performs lawful activities within the United States related to the purposes for which the entity or organization is constituted (e.g., selling goods or providing services to customers, conducting regular training activities, attending conferences), provided such activities are not conducted solely or primarily to permit it to register for a usTLD domain name and are lawful under the laws and regulations of the United States and satisfy policies for the usTLD, including policies approved and/or mandated by the DoC;
Maintains an office or other facility in the United States for a lawful business, noncommercial, educational or governmental purpose, and not solely or primarily to permit it to register for a usTLD domain name.
but I don't know how after years of owning .us domains at different registrars they finally figured out I don't have US citizenship. 
