In this connection Canning wished to bring about the signature, by England, France, and the United States, of "ministerial notes, one between France and the United States, and one between France and Great Britain, or one tripartite note signed by all, disclaiming each for themselves, any intention to occupy Cuba, and protesting against such occupation by either of the others."[87] The government of the United States held this proposal under advisement, but on France declining, it was dropped.[88] In 1826 when an attack upon Portugal was feared Canning advised, in case of such an attack, the immediate seizure of Cuba by Great Britain as more effective than half a dozen Peninsular campaigns.[89] The Cuban question was involved in the long debate on the proposal of the executive of the United States to send delegates to the congress of Spanish-American republics assembled at Panama in 1826. This debate occupied the attention of Congress during the winter and spring of 1826, and was engaged in with great earnestness. One of the chief objections to the proposed mission was the fact that the question of Cuba and Porto Rico would come up and that the United States government had already committed itself to the foreign powers on that subject. The report of the Senate committee on foreign relations declared that, The very situation of Cuba and Porto Rico furnishes the strongest inducement to the United States not to take a place at the contemplated congress, since, by so doing, they must be considered as changing the attitude in which they hitherto have stood as impartial spectators of the passing scenes, and identifying themselves with the new republics.[90] The Southern members were united in their opposition to the Panama mission, and in fact to any closer alliance with the new republics, for the reason that the latter had adopted the principle of emancipation and any further extension of their influence would jeopardize the institution of slavery in the United States. For the same reason they were opposed to the transfer of Cuba to any other European power. If a change from its connection with Spain were necessary they favored annexation by the United States, and meantime they were strongly opposed to the government entering into any engagement with foreign powers or in any way committing itself on the Cuban question.[91] The declaration of Mr. Clay against the interference of England and France in the affairs of Cuba was consistently adhered to under the administrations of Jackson and Van Buren.