As part of their justification for leaving the union after the election of 1860, secessionists argued that the Constitution was a compact among states that could be abandoned at any time without consultation, and that each state reserved the right to secede from the compact. South Carolina invoked the Declaration of Independence to defend their right to secede from the Union, seeing their declaration of secession as a comparable document. In the aftermath of the 1860 election, seven Deep South states passed secession ordinances by February 1861 (before Abraham Lincoln took office as president). Declaring themselves as the Confederate States of America, these seven states elected Jefferson Davis as the provisional president, declared Montgomery the nation's capital, and began raising an army .
After the Confederate attack on Fort Sumter on April 12, 1861, and Lincoln's subsequent call for troops on April 15, four more states declared their secession. By spring 1861, the Confederacy was composed of South Carolina, Mississippi, Florida, Alabama, Georgia, Louisiana, Texas, Virginia, Arkansas, Tennessee, and North Carolina. Although slave-holding Delaware and Maryland did not secede, citizens from those states exhibited divided loyalties, and Lincoln implemented a system of compensated emancipation and slave confiscation from "disloyal citizens" in these border states during the Civil War.
At first, Lincoln tried to pacify the seceeding states in his first inaugural address, in which he explicitly promised to preserve slavery in the states it already existed in, and implied support for the proposed Corwin Amendment, which would have given further protections to slavery in the Constitution. However, efforts by the Confederate States to forcibly remove United States troops and federal presence in its territory (culminating in the Battle of Fort Sumter) pushed the two factions irreversibly towards war.
The United States government did not declare war on the Confederate States, but conducted its military efforts: beginning with a presidential proclamation issued April 15, 1861, which called for troops to recapture Southern forts and suppress a Southern rebellion. Immediately following Fort Sumter, the Confederate Congress declared war against the United States, and the Civil War officially began.
During the four years of its wartime existence, the Confederacy asserted its independence by appointing dozens of diplomatic agents abroad. The United States government, on the other hand, regarded the Southern states in rebellion and refused any formal recognition of their government. They issued warnings to Europe (particularly Britain) that threatened hostile relations if the Confederacy was recognized internationally. Throughout the early years of the war, British foreign secretary Lord John Russell, Napoleon III of France, and other foreign leaders showed interest in recognizing the Confederacy, or at least a mediation in the war. However, Europe remained largely neutral in the Civil War, unwilling to lose trading relations with the United States. At the same time, foreign governments curiously watched the political evolution of the Confederacy and sent military observers to assess Confederate autonomy in the event that the South prevailed in its fight for nationhood.