It was on this day in 1861 that the USS San Jacinto stopped the British mail steamer Trent that was on route to Europe. On board were two envoys of the Confederate States of America bound for London and Paris, James Mason and John Slidell whom the Union forces arrested, took back to the States and put in prison. Up to this point Britain and France had been very cold to the idea of recognizing the Confederacy. Most agreed that such a step would ensure a conflict between the U.S. and Britain and France which would almost certainly result in a Confederate victory in the on-going 'War Between the States'. To date Confederate efforts to woo Britain and France had not met with success, however, the stopping of the Trent caused immediate outrage in Britain in a way that reversed the traditional roles for the U.S. and Britain.
It was not lost on the people of the time that the last time Britain and America went to war (in 1812) it was the U.S. complaining about Britain not respecting the rights of neutral ships, stopping American vessels to carry away British sailors. Nonetheless, the British government demanded a formal apology and the immediate release of the two Confederate envoys. The U.S. public, however, did not react in a very diplomatic war. So far victories on the battlefield had largely eluded them and the capture of the two envoys was heralded as a great triumph for the Union and more or less dared the British to make trouble about it. The British public, on the other hand, were outraged even though opinion had been divided over the war in America. If the matter was not settled the vast majority felt it would be an insult to the very dignity and honor of Great Britain. Lord Palmerston, the prime minister, was positively furious. Much of the British aristocracy had long favored the Confederate cause and took the view that a divided America would be much more in the interests of Britain than a united and expanding one. Preparations for war began to be made.
The Royal Navy was put on alert, the Canadian militia was mobilized and enlarged and more than 10,000 redcoats were soon ready to ship-out to America in the event of war. However, a nervous Queen Victoria asked her consort Prince Albert to look into the situation and he softened the British response to give the U.S. a chance to backdown without much of an admission of guilt. U.S. President Lincoln immediately grasped the opportunity, famously saying that "one war at a time" was enough. The Confederate envoys were released, the U.S. government disavowed the actions of their naval captain and so were not required to make a formal apology. The Union left feeling justified and the British felt victorious with the release of the two envoys who never came closer to success in their aim of winning Britain and France as allies than during the time they were sitting in a Union prison. More than anything else it was the diplomatic intervention of Prince Albert, who was already ill with the sickness that would soon take his life, that prevented Britain going to war with the U.S. which would have had profound consequences on subsequent American history. The U.S. would have faced a 2-front war (when they had so far barely managed the one) and the Royal Navy would have posed a very serious threat to the Union naval blockade of the south that proved instrumental in starving the southern Confederacy into submission. History could have gone very differently indeed.