What was the name of the diplomatic incident where the Confederacy sent diplomats to Britain and France and were captured by a Union ship?

The Trent Affair was a significant diplomatic incident during the American Civil War that occurred in late 1861. It involved the Union navy capturing a British mail ship, the RMS Trent, which was carrying two Confederate diplomats, James Mason and John Slidell, who were seeking recognition and support from Britain and France for the Confederacy. The Union's actions created a diplomatic crisis because it angered the British government, which viewed the capture as a violation of international law and an attack on British sovereignty.

The incident highlighted the Confederacy's reliance on "Cotton Diplomacy," which aimed to leverage cotton exports to secure foreign support, particularly from European powers dependent on Southern cotton for their textile industries. However, the Trent Affair underscored how precarious the Confederacy's diplomatic efforts were and demonstrated the importance of maintaining good relations with foreign nations during the war.

The other options do not relate to the diplomatic incident involving the capture of Confederate diplomats. The War of 1812 refers to a conflict between the United States and Britain, while Marbury v. Madison was a landmark Supreme Court case regarding judicial review. Therefore, the Trent Affair is the correct answer as it specifically pertains to the incident in question.