42 CFR § 407.10 - Eligibility to enroll.
(a)Basic rule. Except as specified in paragraph (b) of this section, an individual is eligible to enroll for SMI if he or she -
(2) Meets the following requirements:
(i) Has attained age 65. (An individual is considered to have attained age 65 on the day before the 65th anniversary of his or her birth.)
(ii) Is a resident of the United States.
(iii) Is a citizen of the United States, or an alien lawfully admitted for permanent residence who has resided continuously in the United States during the 5 years preceding the month in which he or she applies for enrollment.
(b)Exception. An individual is not eligible to enroll for SMI if he or she has been convicted of -
(2) Conspiracy to establish dictatorship under section 4 of the Internal Security Act of 1950.