From 1855 to 1860 the key to the diplomatic history of the country was the fact that the administrations of Pierce and Buchanan, whose chief desires were connected with a policy of southern expansion, were rendered almost powerless by the renewed sectional feeling of the north during the Kansas controversy. The old opposition to extension of slave territory blazed into fresh flame, taking form in scores of speeches in Congress, in newspaper articles, and in party resolutions.

The Republican platform of 1856 declared "that the highwayman's plea that might makes right embodied in the Ostend circular, . . . would bring shame and dishonor upon any government or people that gave it their sanction." Hence, in view of this expressed antipathy of the north to the extension of slave territory, a continuation of the policy begun by Marcy in regard to Cuba and Central America was out of the question.

Although the last years of Pierce's term were marked by a cessation of efforts for annexations, Marcy's conduct of foreign affairs continued to display a defiance of European powers, and a willingness to risk affronting Great Britain in minor matters. During the Crimean War, some recruiting agents, claiming to be authorized by Crampton, the British minister, showed an annoying activity in eastern cities. In spite of Marcy's vigorous protests, Lord Clarendon declined to admit the slightest laxity on the part of his representative; and the upshot was that in May 1856, Pierce took the grave step of declining to hold any further diplomatic intercourse with Crampton. The evidence upon which Marcy and Pierce condemned Crampton was of a highly questionable character, and all that the facts seemed to show was some slight indiscretion on the British minister's part; but although the British press exhibited irritation, the British government took no steps to resent it other than to leave their country unrepresented until Buchanan was inaugurated.

A similar independent attitude was shown by Marcy in attempting to conclude a series of treaties recognizing the principle of "free ships and free goods," and when these were apparently superseded by the Declaration of Paris, in 1856, he declined to commit the United States to that document, partly because it did not recognize the full exemption claimed for neutrals by the United States, and partly because it abolished the traditional American practice of privateering in wartime. In the same years, Marcy forced the Danish government to consent to abandon its ancient "Sound dues" and commute all claims by a money payment in a treaty concluded in 1857. In these cases, Marcy's conduct of the state department retained to the end its characteristic vigor, a quality which causes it to stand out prominently in the era between Polk and Lincoln.

The Central American question, meanwhile, became so complicated as to justify Marcy's reluctance to commit the United States to any responsibility in that quarter. As soon as it became manifest that the Pierce administration was likely to fall short of the desires of the cotton states for tropical annexation, the filibustering spirit reappeared, in a sudden and dramatic attempt to seize Nicaragua, the very country which controlled the proposed canal and the existing Transit Company. William Walker, a military adventurer with a previous record of unsuccessful filibustering against Mexico, joined in the chronic Nicaraguan civil wars with a handful of followers as an adherent of the "liberal" faction, and by force or trickery succeeded in making away with Corral, the "legitimate" leader, and establishing himself in control behind Rivas, a nominal president. For two years he remained the real dictator of Nicaragua, stirring up great sympathy in the southern states, where he was looked upon as "the gray-eyed man of destiny," a second Houston, and Nicaragua was regarded as another Texas.

Walker soon undermined his power by his severity and by a series of mistakes, the most serious of which was the confiscation of the charter and the steamers of the Accessory Transit Company, upon an outrageous pretext, for the benefit of two confederates. By this act, he won the bitter enmity of the steamship company, headed by Cornelius Vanderbilt, which had been the means of bringing him supplies and reinforcements, and without which he was cut off from his supporters in the United States. Then he deposed Rivas, caused himself to be elected president in July 1856, issued a decree opening Nicaragua to slavery, and invited American capital. His government was recognized at Washington, but by this time his behavior had set all the other Central American states against him; war soon broke out, and Walker found himself attacked by overwhelming numbers while cut off from reinforcements by the vengeful Transit Company. By the end of Pierce's term, after furious fighting, his forces were worn down, and in the spring of 1857, he was finally driven out, being taken from the city of Rivas, where he surrendered, by an American man-of-war.

The result of these events was the destruction of any influence possessed by the United States with the Central American states, whose leaders looked upon Walker as representing the sentiment of the American people. Marcy's diplomacy was deprived of all support from Central American sources and was hindered by the uncertainty attending the outcome of Walker's schemes. All that was accomplished by Dallas, the successor of Buchanan at the court of St. James, was an agreement with Lord Clarendon (October 1856) by which Great Britain undertook to limit Belize, withdraw from the Mosquito protectorate, and restore the Bay Islands to Honduras, provided Honduras agreed to a treaty guaranteeing to the Bay Islands a sort of self-government. This proposition was pending before the Senate at the end of Pierce's term, a lame conclusion to the strenuous beginning of Marcy's Central American diplomacy.

When Buchanan assumed control of the government there could be no doubt as to the course that the Democratic party wished him to adopt. The party platform declared that "there are questions connected with the foreign policy of this country which are inferior to no domestic questions whatever," and announced its approval of Walker's attempt "to regenerate that portion of the continent which covers the passage across the inter-oceanic isthmus." The platform went so far as to advocate the control by the United States of the transit route, which "no power on earth should be suffered to impede," and declared for the maintenance of "our ascendency in the Gulf of Mexico." Buchanan himself was part author of the Ostend Manifesto and had a large majority of each House of Congress at his back. But Buchanan was not a president to venture any positive policy unless he felt a secure backing from the other departments of government. He was by this time an old man, whose entire record had been one of caution in action and of reluctance to incur responsibility. Heartily anxious to please the southern advocates of annexation, as he was to satisfy their desires in Kansas, he would have been glad to gratify their utmost hopes; but unless he could secure definite authorization in advance from Congress he would not take a step. No more radical action was to be expected from the secretary of state, Lewis Cass, once a belligerent Anglophobe, but now a man of seventy-five years, and, if Buchanan's later testimony be believed, grown helplessly inert and irresolute. A more cautious pair of statesmen never undertook to deal with the foreign affairs of a country on a radical platform.

The first annual message of Buchanan, December 1857, stigmatized filibustering as "robbery and murder," and recommended that Congress take the matter in hand. This was characteristic of Buchanan, to take strong ground in a public message and end by laying all responsibility upon Congress. At that very moment, Walker, still claiming to be president of Nicaragua, traveled in the south as a popular hero, raised a new expedition, and prepared to try his luck again on the isthmus. The Central American ministers sent heated protests, and Walker was compelled to give bonds for two thousand dollars to obey the laws; but, undisturbed by Buchanan's censure, he evaded federal collectors and attorneys and sailed to the San Juan River in November 1857. Here his career was brought to a sudden halt, for before he could invade Nicaragua his force was taken prisoner by Commodore Paulding, of the United States Navy, and brought back to the country they had left.

A perfect hornet's-nest was raised about the ears of the unfortunate Paulding. He was denounced in the newspapers, pilloried in each House of Congress as guilty of high-handed outrage, and censured by Buchanan for exceeding his instructions and violating the neutrality of a foreign country. But although Walker was instantly set at liberty, and, when tried for violating the neutrality laws, was promptly acquitted by a New Orleans jury, the result of Paulding's action proved decisive. Nicaragua formally thanked the United States, disavowed a grant to a rival French canal scheme, and, with Costa Rica, revoked hostile decrees recently issued against the United States. Walker was not able to renew his filibustering until i860 when he met his death in an expedition against Honduras, and by that time a settlement of the isthmian difficulty had been attained through diplomatic channels.

The Dallas-Clarendon treaty, which was pending when Buchanan assumed office, was amended by the Senate so as to eliminate any reference to the proposed treaty between Honduras and Great Britain, and left standing a simple recognition of the sovereignty of Honduras over the Bay Islands. This in turn was rejected by her majesty's government, and, after a fruitless attempt to renew the treaty in a form acceptable to both sides, affairs seemed to have come to a deadlock. A treaty with Nicaragua, made by Cass, which gave the United States the right to defend the canal route in case of war, while still guaranteeing its neutrality, failed to make the situation any clearer. Buchanan then turned, as usual, to Congress, and in his first message intimated that an abrogation of the Clayton-Bulwer treaty would be the only solution.

This threat spurred the British government to action. Lord Napier and Sir William Ouseley, at Washington, pointed out the embarrassments of returning to the condition of things in 1849 and urged arbitration of the true meaning of the treaty. They observed, also, that if the treaty were abrogated Great Britain would of course be left free to consult her own interests on the isthmus, a remark which had a calming effect upon Cass and Buchanan. The idea of renewing the scramble of 1848-1850 was distinctly unwelcome to either of them and so, although declining to arbitrate, they agreed to wait, provided Great Britain would seek to conclude treaties with the Central American states on the lines of the American contention.

This plan was actually carried out, and between 1857 and 1860 Great Britain made conventions settling the boundaries of Belize, ceding the Bay Islands to Honduras and the Mosquito protectorate to Nicaragua, on condition of self-government for the ceded regions and an annual subvention, in default of which Great Britain could again intervene. Little as these treaties accorded with the adjustment which Clayton supposed he was making in 1850, or the claims put forward by Marcy, they were accepted and proclaimed by Buchanan as "a final settlement entirely satisfactory to this Government."

Buchanan's habitual waiting upon Congress in matters of importance effectually prevented any resumption of Cuban diplomacy during his term. In his second annual message, December 1858, Buchanan repeated, although in milder tones, the arguments of the Ostend Manifesto, not forgetting to refer to circumstances that might render the seizure of the island justifiable under "the law of self-preservation." In response to his request for congressional support, a bill for the appropriation of thirty million for the purchase of Cuba was introduced into the Senate, but it was never brought to a decisive vote. Again, in his third message, December 1859, Buchanan laid the matter before Congress, but without avail. The result was that no action whatever was taken regarding Cuba, in spite of the language of the Democratic platform. Even an attempt to settle the vexatious losses of American citizens at the hands of Cuban officials was blocked because the Senate refused to accept a convention with Spain on the ground of its inclusion of the Amistad claim.

Towards Mexico, where the Conservative or Clerical party, in the course of chronic civil war, had been guilty of numerous outrages upon American citizens, Buchanan recommended the adoption of drastic measures. In 1858 he suggested that the United States assume a protectorate over the northern part of Mexico, and in 1859 he asked for authority to invade the country to restore order. Needless to say, such suggestions were entirely unwelcome to the northern members of Congress and were ignored. The Senate would not even consider two treaties of 1859, by which the United States was to assume claims against Mexico in return for commercial concessions, and allowed the proposed agreements to die unnoticed.

In one case only did Buchanan gain the backing he sought. In response to a recommendation in the message of 1857, Congress authorized an expedition to Paraguay, which sailed with nineteen vessels, forced an apology for an insult offered to the United States steamer Water Witch in 1855, gained a commercial treaty, and made an agreement for a commission to investigate an American claim for damages. This success over the small and distant Paraguay was the only positive action in external affairs that even remotely carried out the spirit of the Democratic platform.

In the far east the United States secured diplomatic victories during Buchanan's term, but only by the ordinary methods of negotiation, directed with caution and shrewdness. In China, the Cushing treaty of 1845 had not proved wholly adequate, and a succession of American ministers had worn out their patience trying to secure a new commercial treaty with a Chinese government whose foreign minister refused even an interview. When, in 1856-1858, England and France became involved in a war with China, and their vessels bombarded the Barrier forts, the United States managed to profit from the circumstances. Cass declined participation in the allied attack, but Reed, the American minister, steering his own course, succeeded in securing a treaty of commerce in June 1858, which was solemnly ratified the next year. At the same time, additional privileges were gained from Japan by treaties concluded in 1857 and 1859 through Townsend Harris. As a result of these Oriental negotiations, our commercial relations were placed on a better footing than ever before, a worthy diplomatic success gained without committing the country to any belligerent foreign policy.

In another quarter, also, a diplomatic success may be credited to Buchanan and Cass, although won in a field where little glory was to be reaped. In the years before i860, there took place a sharp rise in the price of slaves, and, in consequence, the African slave trade to Cuba and the United States increased surprisingly. The law was violated with impunity, and Buchanan's administration seemed unable or unwilling to prevent the traffic. But when British cruisers, in 1857 and 1858, searched suspected American vessels, not only off the coast of Africa but even in the Gulf of Mexico, the administration roused itself and protested strenuously against this renewed claim to a right of search. Secretary Toucey ordered United States men-of-war to proceed to Cuban waters to protect American vessels from "outrage," but the whole affair was ended with bewildering suddenness by the prompt admission of Lord Malmesbury to Dallas that the British government accepted entirely the principles laid down by Cass in his protests. This unexplained, voluntary concession of the point at issue was regarded by Cass and Buchanan as a great triumph. It was followed by a long discussion over means of verifying the nationality of vessels so as to prevent abuse of the flag by slave traders, but Cass adopted a negative attitude and nothing had been accomplished when Buchanan went out of office. The same was true regarding a disagreement that developed concerning the ownership of certain islands in Puget Sound which was left for a later administration to settle.

The diplomatic history of the decade 1850-1860 concluded with a defeat for territorial expansion in almost every quarter. The opportunity for embarking the country upon an aggressive foreign policy, which seemed open at the beginning of Pierce's term, was lost when the Kansas-Nebraska act once more stirred up sectional antagonism. Cuba still remained under the Spanish yoke and American losses in the island remained unsettled. Mexico continued to seethe in her internal conflicts without intervention from her neighbor, but from the northeastern frontier to the Central American isthmus no further cause of controversy appeared. By luck or diplomatic skill, by violence or compromise, a settlement had been attained of every serious diplomatic controversy.