In response to the increased anti-slavery agitation that followed the Dred Scott decision (1857), the Knights changed their position: the Southern United States should secede, forming their own confederation, and then invade and annex the other areas of the Golden Circle.

[3] During the American Civil War, Southern sympathizers in the United States, especially that Northern United States, such as in Ohio, Illinois, Indiana, Minnesota, and Iowa, were organized to a radical paramilitary splinter group of KGC, which was renamed, in a deliberate reference to the American Revolution, the "Order of the Sons of Liberty".

The Spanish possessions of Cuba and Puerto Rico and the Empire of Brazil continued to depend on slavery, as did the Southern United States.

In the years before the American Civil War, the rise of support for the abolition of slavery was one of several divisive issues in the United States.

George W. L. Bickley, a doctor, editor, and adventurer who was born in Indiana[4] and lived in Cincinnati, Ohio, founded the association, organizing the first castle, or local branch, in Cincinnati in 1854,[5] although records of the KGC convention held in 1860 state that the organization "originated at Lexington, Kentucky, on the fourth day of July 1854, by five gentlemen who came together on a call made by Gen. George Bickley".

[6] Hounded by creditors, Bickley left Cincinnati in the late 1850s and traveled through the eastern and southern United States, promoting an armed expedition to Mexico.

[7] In the North, the KGC was cited by a Senator from Wisconsin as an exemplar of "Southern fanaticism", an exposé of the organization was published in Indiana in 1861, and its secret rituals were publicized in Boston in that year as well.

[8] The initiation ritual of the KGC began: "the first field of our operations is in Mexico; but we hold it to be our duty to offer our services to any Southern State to repel a Northern army ...

A candidate who was born in a Slave State need not be a Slaveholder provided he can give Evidence of character as a Southern man."

Robert Barnwell Rhett, who has been called "the father of secession", said a few days after Lincoln's election: We will expand, as our growth and civilization shall demand—over Mexico—over the isles of the sea—over the far-off Southern tropics—until we shall establish a great Confederation of Republics—the greatest, freest and most useful the world has ever seen.

[10]In 1859, future Confederate States Army brigadier general Elkanah Greer established KGC castles in East Texas and Louisiana.

[11] In the spring of 1860, Elkanah Greer had become general and grand commander of 4,000 Military Knights in the KGC's Texas division of 21 castles.

The Texas KGC supported President of the United States James Buchanan's policy of, and draft treaty for, protecting routes for U.S. commerce across Mexico, which also failed to be approved by the U.S.

[14] As volunteers continued to join McCulloch the following day, United States Army Brevet Maj. Gen. David E. Twiggs surrendered the arsenal peacefully to the secessionists.

[15] KGC members also figured prominently among those who, in 1861, joined Lt. Col. John Robert Baylor in his temporarily successful takeover of southern New Mexico Territory.

[16] In May 1861, members of the KGC and the Confederate Rangers attacked a building that housed a pro-Union newspaper, the Alamo Express, owned by J. P. Newcomb, and burned it down.

In early 1862, Radical Republicans in the Senate, aided by Secretary of State William H. Seward, suggested that former president Franklin Pierce, who was exceedingly critical of the Lincoln administration's war policies, was an active member of the Knights of the Golden Circle.

Leaders of the Democratic Party opposed to Abraham Lincoln's administration denounced the draft and other wartime measures, such as the arrest of seditious persons and the president's temporary suspension of the writ of habeas corpus.