By February 1861, 7 Deep South states had seceded and formed the Confederate States of America. President Buchanan’s administration was in its last lame-duck days. The upper South, Virginia, Maryland, Kentucky, Tennessee, Arkansas and Missouri, tottered between North and South, union or rebellion.
Missouri governor Claiborne Fox Jackson was a southern sympathizer. He argued for secession at the State Convention convened in Jefferson City and chaired by former governor Sterling Price. Missourians tended toward moderate Unionist views and did not support war against the Confederacy. The powerful Blair family, lead by congressman Frank and postmaster-general-designate Montgomery, supported a Republican organization opposing secession known as the ‘Wide-Awakes’ who managed to arm themselves with weapons from Illinois. On March 21, the convention voted 98-1 against secession.
In St. Louis sat the Arsenal, containing 60,000 muskets, 45 tons of gunpowder and 1½ million cartridges, the largest supply of arms and ammunition in the West – invaluable to Union and Confederate alike. The arsenal was commanded by General William S. Harney and supervised by Major Peter Hagner. Into this fractious, albeit balanced situation, was transferred Captain Nathaniel Lyon.
Lyon’s reputation was one of a stern disciplinarian, outspoken political radical, Blair ally, and hothead. Lyon, wishing to secure Missouri for the Union, hoped to muster the Wide-Awakes into federal service and arm them from the arsenal. Hagner denied this request. After Lincoln’s inauguration on March 4th, Lyon implored Frank Blair to exert his influence and have Lyon appointed the Arsenal’s commander. Blair did so and also arranged to have Harney called east for ‘consultations’. One week after Fort Sumter, on April 21, Lyon armed the Wide Awakes, sent all but 10,000 muskets across the river into Illinois and prepared to neutralize the Confederate Missouri State Guard encampment at Camp Jackson.
On May 10, Lyon surrounded the CSA Camp and bloodlessly disarmed the 700 men. Refusing to take the oath of allegiance, Lyon marched the prisoners through the streets of St. Louis before paroling them. The captured men’s public humiliation provoked pro-Southern civilians into throwing insults, fruits and cobblestones at Lyon’s, mostly German, forces. Then shots rang out, killing 3 of Lyon’s men. A return volley killed 25 men, women and children and wounded another one hundred. Scattered rioting and violence continue for 2 days and another seven civilians died.
Returning to St. Louis on May 12, Harney hoped to calm the situation. He met with Price on May 23rd and they issued a truce, reading in part:
“General Price, having by commission full authority over the militia of the State of Missouri, undertakes, with the sanction of the governor of the State, already declared, to direct the whole power of the State officers to maintain order within the State among the people thereof, and General Harney publicly declares that, this object being thus assured, he can have no occasion, as he has no wish, to make military movements, which might otherwise create excitements and jealousies which he most earnestly desires to avoid”
The truce stabilized the political situation but did not calm Lyon. On May 30, Blair had Harney dismissed and replaced by Lyon, now promoted to General. On June 11, Governor Jackson, suffering from stomach cancer, and Price and their staff met with Blair and Lyon and several aides. Jackson offered Lyon a position of Unionist neutrality in exchange for Lyon’s forces leaving the state.
After a day of fruitless discussion, Lyon’s temper got the best of him. He leapt to his feet and ranted, “Rather than concede to the State of Missouri the right to demand that my government shall not enlist troops within her limits, or bring troops into the State whenever it pleases, or move troops at its own will into, out of, or through the State; rather than concede to the State of Missouri for one single instant the right to dictate to my government in any matter, however unimportant, I would see you, and you, and you, and you and every man, woman and child in the State, dead and buried. This means war. In an hour one of my officers will call for you and conduct you out of my lines.”
Jackson returned to Jefferson City where he reminded Missourians to “obey all the constitutional requirements of the Federal Government" but there was "no obligation whatever to obey the unconstitutional edicts of the military despotism" and its "wicked minions," in other words, General Nathaniel Lyon.
Lyon moved his forces toward the capital and Jackson and Price retreated to Boonville. Lyon occupied Jefferson City on May 14, assembled a new State Convention and formed a pro-Union State Government under Governor Hamilton R. Gamble. The 'other' Governor Jackson and his associates and sympathizers retreated west and south.