42 CFR §407.10

1. (a)Basic rule. Except as specified in paragraph (b) of this section, an individual is eligible to enroll for SMI if he or she—
   1. (1)Is entitled to hospital insurance under any of the rules set forth in §§ 406.10 through 406.15 of this chapter; or
   2. (2)Meets the following requirements:
      1. (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.)
      2. (ii)Is a resident of the United States.
      3. (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.
2. (b)Exception. An individual is not eligible to enroll for SMI if he or she has been convicted of—
   1. (1)Spying, sabotage, treason, or subversive activities under chapter 37, 105, or 115 of title 18 of the United States Code; or
   2. (2)Conspiracy to establish dictatorship under section 4 of the Internal Security Act of 1950.