Porto Rico

Moreover, Polk's announcement regarding Yucatan was quite in line with that of his predecessors with respect to Cuba, and the degree of importance does not affect the principle involved. For example, when Secretary Clay, by order of President Adams, notified France and other powers that we could not consent to the occupation of Cuba and Porto Rico "by any other European power than Spain under any contingency whatever,"¹⁸ he was thinking of the transfer per se and of the effect upon the United States, and not of the wishes of the Cubans.

1922, Eugene Irving McCormac, “The "Polk Doctrine" and Minor Diplomatic Questions”, in James K. Polk: A Political Biography, Berkeley, Cali.: University of California Press, →OCLC, pages 698–699