When open fighting broke out between Pro-Confederate governor Claiborne Fox Jackson and Union authorities, and Union forces occupied the state capital, the convention formed a provisional state government, and functioned as a quasi-legislature for several years.
The election was scheduled for 18 February, with three delegates chosen from each state senate district (99 total).
In addition, by an amendment submitted by Charles H. Hardin, a secession declaration by the convention would have to be ratified in a referendum by a majority vote of the state's qualified voters.
[5] The convention resolved: That at present there is no adequate cause to impel Missouri to dissolve her connection with the Federal Union, but on the contrary she will labor for such an adjustment of existing troubles as will secure the peace, as well as the rights and equality of all the States.
[6][7]The convention established a Federal relations committee, with unconditional unionist Hamilton Rowan Gamble as chairman.
The position of Missouri in relation to the adjacent States which would continue in the Union, would necessarily expose her, if she became a member of a new confederacy, to utter destruction whenever any rupture might take place between the different republics.
Governor Jackson rejected the request, declaring it to be illegal, arguing that the constitution gave no authority to the federal government to make war on the states.
He called out the state militia, appointed pro-secession officers to command it, and obtained artillery from the Confederacy.
Union forces under U.S. Army Captain Nathaniel Lyon reacted on 10 May surrounding the militia and taking them prisoner in the Camp Jackson Affair.
This drastic action prompted the General Assembly to pass a military bill proposed by Governor Jackson, which reorganized the militia as the Missouri State Guard.
Lyon then marched his forces on Jefferson City, entering the undefended state capital on 15 June.
In this session, the convention imposed its loyalty oath on teachers, attorneys, bank officers, and preachers, and on voters, thereby ensuring a strong Union vote in future elections.
The major obstacle was a provision in the constitution that required consent of the slave's owner and payment of compensation.
This plan for gradual emancipation infuriated the Radical Republicans, who wanted slavery abolished immediately.
A month later the convention approved the Thirteenth Amendment to the United States Constitution to abolish slavery throughout the U.S.