All citizens of the United States who have resided or who shall after March 4, 1927, reside in the island for one year shall be citizens of Puerto Rico.
(Mar. 2, 1917, ch. 145, § 5a, as added Mar. 4, 1927, ch. 503, § 2, 44 Stat. 1418; amended May 17, 1932, ch. 190, 47 Stat. 158.)