In 1838-39, the British government dispatched special commissioners to Cuba and Porto Rico to report on the condition of the slave trade. The presence of these agents in Cuba gave rise to reports that Great Britain contemplated revolutionizing the island, or at least occupying it for the purpose of suppressing the slave trade. The United States gave Spain to understand that we would not consent to British control in whatever way it might be brought about. Mr. Forsyth wrote to Mr. Vail, our representative at Madrid, July 15, 1840: You are authorized to assure the Spanish government, that in case of any attempt, from whatever quarter, to wrest from her this portion of her territory, she may securely depend upon the military and naval resources of the United States to aid her in preserving or recovering it.[92] Again, Mr. Webster in January, 1843, wrote to Mr. Campbell, United States consul at Havana: The Spanish government has long been in possession of the policy and wishes of this government in regard to Cuba, which have never changed, and has repeatedly been told that the United States never would permit the occupation of that island by British agents or forces upon any pretext whatever; and that in the event of any attempt to wrest it from her, she might securely rely upon the whole naval and military resources of this country to aid her in preserving or recovering it.[93] A copy of this letter was also sent to Washington Irving, our representative at Madrid to make such use of as circumstances might require.[94] During the first period of our Cuban diplomacy the efforts of this government were directed toward preventing the acquisition of the island, or the establishment of a protectorate over it, by Great Britain or France. With the Mexican war, however, and the growing conviction of "manifest destiny," our foreign policy assumed a much bolder and more aggressive character, and during the next fifteen years all manner of schemes for the southward extension of our territory were suggested and many of them actually undertaken. Cuba became an object of desire, not only in the eyes of the slave-holding population of the South as an acquisition to slave territory, but of a large part of the nation, because of its strategic importance in relation to the inter-oceanic transit routes of Central America, which seemed the only feasible line of communication with our rapidly developing interests in California. Consequently various attempts were made to annex the island to the United States, both by purchase from Spain and forcibly by filibustering expeditions.