Contrary to a widely prevailing opinion the Monroe Doctrine has undergone very little change since the original declaration, and the official statements of the doctrine have on the whole been very consistent. The only important extension was made less than two years after the original declaration, when, in October, 1825, Secretary Clay, acting under the direction of President John Quincy Adams, who assisted in formulating the doctrine, notified the French government that we could not consent to the occupation of Cuba and Porto Rico "by any other European power than Spain under any contingency whatever." Similar declarations were made to the other European powers, the occasion being the fear that Spain would transfer her sovereignty over these islands to some other government. President Monroe had declared that the American continents were closed to colonization from Europe, meaning by colonization very probably, as Professor John Bassett Moore says, "the acquisition of title to territory by original occupation and settlement."[291] He had made no declaration against the transfer of sovereignty in America from one European power to another. In fact he positively renounced any such idea, when he said: "With the existing colonies or dependencies of any European power we have not interfered, and shall not interfere." Here, then, within two years we have a distinct advance upon the position taken by President Monroe. Yet this advanced ground was held by succeeding administrations, until President Grant could say in the case of the same islands in his first annual message: These dependencies are no longer regarded as subject to transfer from one European power to another. When the present relation of colonies ceases, they are to become independent powers, exercising the right of choice and of self-control in the determination of their future condition and relations with other powers.[292] And Secretary Hamilton Fish said a few months later that the President had but followed "the teachings of all our history" when he made this statement.[293] The failure of Blaine and Frelinghuysen to oust Great Britain from her interests in the canal under the Clayton-Bulwer treaty by an appeal to the Monroe Doctrine and the successful enforcement of the doctrine by President Cleveland and Secretary Olney in 1895 have been discussed at sufficient length in previous chapters. While the policy of Cleveland and Olney was vehemently denounced at the time, it is now generally approved by American writers of authority on international law and diplomacy.