The Trent Affair was a diplomatic incident in 1861 during the American Civil War that threatened a war between the United States and the United Kingdom. The U.S. Navy illegally captured two Confederate diplomats from a British ship; the UK protested vigorously. The United States ended the incident by releasing the diplomats.
Public reaction in the United States was to celebrate the capture and rally against Britain, threatening war. In the Confederate States, the hope was that the incident would lead to a permanent rupture in Anglo-American relations and possibly even war or at least diplomatic recognition by Britain. Confederates realized their independence potentially depended on intervention by Britain and France. In Britain, the public disapproved of this violation of neutral rights and insult to their national honor. The British government demanded an apology and the release of the prisoners and took steps to strengthen its military forces in Canada and the Atlantic.
President Abraham Lincoln and his top advisors did not want to risk war with Britain over this issue. After several tense weeks, the crisis was resolved when the Lincoln administration released the envoys and disavowed Captain Wilkes's actions, though without a formal apology. Mason and Slidell resumed their voyage to Britain but failed in their goal of achieving diplomatic recognition.
Relations with the United States were often strained and even verged on war when Britain almost supported the Confederacy in the early part of the American Civil War. British leaders were constantly annoyed from the 1840s to the 1860s by what they saw as Washington's pandering to the democratic mob, as in the Oregon boundary dispute in 1844 to 1846. However, British middle-class public opinion sensed a common "Special Relationship" between the two peoples, based on language, migration, evangelical Protestantism, liberal traditions, and extensive trade.
During the affair, London drew the line and Washington retreated.
The Confederacy and its president, Jefferson Davis, believed from the beginning that European dependence on Southern cotton for its textile industry would lead to diplomatic recognition and intervention, in the form of mediation. Historian Charles Hubbard wrote:
Davis left foreign policy to others in government and, rather than developing an aggressive diplomatic effort, tended to expect events to accomplish diplomatic objectives. The new president was committed to the notion that cotton would secure recognition and legitimacy from the powers of Europe. One of the Confederacy's strongest hopes at the time was the belief that the British, fearing a devastating impact on their textile mills, would recognize the Confederate States and break the Union blockade. The men Davis selected as secretary of state and emissaries to Europe were chosen for political and personal reasons—not for their diplomatic potential. This was due, in part, to the belief that cotton could accomplish the Confederate objectives with little help from Confederate diplomats.
The Union's main focus in foreign affairs was just the opposite: to prevent any British recognition of the Confederacy. Notwithstanding a relatively minor border incident in the Pacific Northwest, Anglo-American relations had steadily improved throughout the 1850s. The issues of the Oregon territory, British involvement in Texas, and the Canada–US border dispute had all been resolved in the 1840s. Secretary of StateWilliam H. Seward, the primary architect of American foreign policy during the war, intended to maintain the policy principles that had served the country well since the American Revolution: non-intervention by the United States in the affairs of other countries and resistance to foreign intervention in the affairs of the United States and other countries in the Western Hemisphere.
British Prime Minister Lord Palmerston urged a policy of neutrality. His international concerns were centered in Europe, where both Napoleon III's ambitions in Europe and Bismarck's rise in Prussia were occurring. During the Civil War, British reactions to American events were shaped by past British policies and their own national interests, both strategically and economically. In the Western Hemisphere, as relations with the United States improved, Britain had become cautious about confronting the United States over issues in Central America.
As a naval power, Britain had a long record of insisting that neutral nations honor its blockades of hostile countries. From the earliest days of the war, that perspective would guide the British away from taking any action that might have been viewed in Washington as a direct challenge to the Union blockade. From the perspective of the South, British policy amounted to de facto support for the Union blockade and caused great frustration.
The Russian Minister in Washington, Eduard de Stoeckl, noted, "The Cabinet of London is watching attentively the internal dissensions of the Union and awaits the result with an impatience which it has difficulty in disguising." De Stoeckl advised his government that Britain would recognize the Confederate States at its earliest opportunity. Cassius Clay, the US minister in Russia, stated, "I saw at a glance where the feeling of England was. They hoped for our ruin! They are jealous of our power. They care neither for the South nor the North. They hate both."
At the beginning of the Civil War, the U.S. minister to the Court of St. James was Charles Francis Adams. He made clear that Washington considered the war strictly an internal insurrection affording the Confederacy no rights under international law. Any movement by Britain towards officially recognizing the Confederacy would be considered an unfriendly act towards the United States. Seward's instructions to Adams included the suggestion that it be made clear to Britain that a nation with widely-scattered possessions, as well as a homeland that included Scotland and Ireland, should be very wary of "set[ting] a dangerous precedent".
Lord Lyons, an experienced diplomat, was the British minister to the US. He warned London about Seward:
I cannot help fearing that he will be a dangerous foreign minister. His view of the relations between the United States and Great Britain had always been that they are a good material to make political capital of.... I do not think Mr. Seward would contemplate actually going to war with us, but he would be well disposed to play the old game of seeking popularity here by displaying violence toward us.
Despite his distrust of Seward, Lyons, throughout 1861, maintained a "calm and measured" diplomacy that contributed to a peaceful resolution to the Trent crisis.