Clayton-Bulwer Treaty of 1850: Anglo-American Epilogue of the Mexican-American War (1846–8)

American diplomat Elija Hise’s journey to Guatemala in 1848 was the embodiment of the obstacles expansionists faced south of the Rio Grande and the reason Americans needed to deal diplomatically with the British to avoid a war centering around the isthmian contest that intensified after the Mexican conflict. In essence, the Clayton-Bulwer Treaty of 1850, designed to mitigate hostilities arising out of Central America, amounted to a geopolitical and continental epilogue to the 1848 Mexican-American War and Treaty of Guadalupe Hidalgo. Imperfect as it was, the agreement was successful in that it prevented an immediate confrontation over a region both sides believed was essential to their future geostrategic and commercial interests. Although the Americans may have invoked, ‘the doctrines of Mr. Monroe and Mr. Polk,’ which emerged out of the Yucatan debate and became known in 1849 as the ‘Monroe Doctrine,’ it was during the post-war period that Americans realized they could not dictate terms to their British rivals. In the end, American expansion southward was not only restricted by British actions affecting Yucatan, but Central America as well.(1)

RIGHT: John Clayton, United States Senator from Delaware. Daguerreotype collection. Source: Library of Congress Prints and Photographs Division Washington, D.C. 20540 USA.

Central America and ‘Monroe Doctrine’

While American soldiers were coming home from Mexico, the situation in Yucatan was eclipsed by Central America. Essentially, the westward movement of people forced an Anglo-American contest over the isthmus – the region facilitating much of the expected migration. More precisely, the ratification of the Bidlack Treaty (1846) with New Granada (Panama) granting the U.S. certain rights to the Panamanian isthmus put pressure on the British to retain their possession of San Juan and protectorate over the Mosquito Kingdom on the east coast of Nicaragua. In an early 1849 article titled, “Bridging the Continent,” the Baltimore Sun summed up the arrangement: “This treaty, therefore, is but a simple advertisement to all the world that for the next twenty years, at least, we will, with the permission of New Granada, cross the Isthmus of Panama, and you must not interfere.”(2)

Clayton-Bulwer Treaty

Throughout the winter of 1850, Delaware Whig senator-turned-Secretary of State John M. Clayton met with Sir Henry Bulwer to settle the matter amicably despite detractors critical of the U.S. deferring to Great Britain when it came to matters they believed existed only between the U.S. and the respective states of Central America. In that regard, there was little Clayton could do to mitigate the scorn directed at him other than endure. Even officials from the former administration, particularly Buchanan, were sensitive to the “assailings” of critics claiming they did not uphold the “Monroe Doctrine against European colonization on this continent” – a doctrine that by 1850 had acquired new meaning. On April 13, a few days before the Clayton-Bulwer Treaty was signed, Buchanan wrote to journalist Francis J. Grund, addressing public complaints from Horace Greely in the New-York Tribune: "The last administration have given so many proofs of their devotion to the Monroe doctrine that it is now, too late in the day to dispute it: & they were never afraid, upon any proper occasion, to avow it to the world. They twice did so, in the face of Great Britain, whilst the Mexican war was raging; although they well knew how hostile the government of that country was to us in this war & how friendly to Mexico." (3)

The Clayton-Bulwer Treaty was an imperfect arrangement that continued to be scrutinized long after its ratification. It was successful, however, in that it served as a legal mechanism designed to prevent war, and slowed the passions of those who might otherwise act headlong without consulting the government. In other words, it served as a means to deescalate tensions arising from the isthmian frenzy that occupied the naval powers of the North Atlantic as a result of the Mexican War. It pledged cooperation in the construction of a canal (that did not materialize until the twentieth century), urged neutrality for shipping and commerce, and stayed the tendency to establish colonies or protectorates to further geostrategic objectives of the two states.

RIGHT: British politician Sir Henry Bulwer was in charge of drafting and negotiating the treaty. 1st Baron Dalling and Bulwer. Source: Art UK.

The treaty would be violated, expeditions to Latin America continued, the Caste War remained, and despite all the evidence to the contrary, some still believed the American sphere could be enlarged beyond the gulf. In late 1850, President Millard P. Fillmore, who replaced Zachary Taylor after his sudden death, stated in a presidential message to Congress that he hoped the treaty would serve as a “harmonizing” force for “conflicting claims to territory” and that “the two governments will come to an understanding.” More importantly, he stated that it was “an imperative duty not to interfere in the government or internal policy of other nations… in their struggle for freedom, our principles forbid us from taking any part in such foreign contests.” That sentiment, more aspirational than practical, was more emulative of how that president may have looked upon his nation, and the desire to put the war in the past to begin anew in the spirit of traditional foreign policy. The war was over, the soldiers and sailors had come home, and therefore it was easier to invoke a more cordial and accommodating resonance reflective of the Civil War he and others were working to prevent:

We make no wars to promote or to prevent successions to thrones; to maintain any theory of a balance of power; or to suppress the actual government which any country chooses to establish for itself. We instigate no revolutions, nor suffer any hostile expeditions to be fitted out in the United States to invade the territory or provinces of a friendly nation. We should act towards other nations as we wish them to act towards us; and justice and conscience should form the rule of conduct between governments, instead of mere power, self-interest, or the desire of aggrandizement. To maintain a strict neutrality in foreign wars, to cultivate friendly relations, to reciprocate every noble and generous act, and to perform punctually and scrupulously every treaty obligation – these are the duties which we owe other states…(4)

Notes: 

1) The following is an amended excerpt from: Benjamin J. Swenson, Wars of the Mexican Gulf: The Breakaway Republics of Texas and Yucatan, US-Mexican War, and Limits of Empire, 1835-1850 (Barnsley, UK: Pen and Sword, 2024).
2)  “Bridging the Continent” The Sun, Baltimore, Jan. 20, 1849. See: H. W. Brands, The Age of Gold: The California Gold Rush and the New American Dream (New York: Anchor Books, 2002).
3)  John Bassett Moore, ed. The works of James Buchanan, comprising his speeches, state papers, and private correspondence; vol. 8 (Philadelphia, London, J.B. Lippincott Company, 1909), 377-381. Buchanan to Francis J. Grund, April 13, 1850.
4)  Congressional Globe, 31st Congress, 2nd Session, 2. Dec. 2, 1850