i dont know if this has been asked before but since Kentucky & Missouri both declared to be neutral at the beginning of the war until the CSA invaded them what would change if the confederacy decided to honor their neutrality & never invaded? my two scenerios would be
A. both countries honer the states neutrality so an important front is taken out of the picture. what would that change for the war?
B. the Union decides to move into Kentucky & Missouri. Would this cause one or both of the states to seccede &/or have more people side with the confederacy? what this change for the war?
Missouri did not declare neutrality. Missouri elected a state convention, which met, voted against secession, and adjourned, all in early 1861 (before the bombardment of Fort Sumter). However, Governor Claiborne Jackson was a crypto-secessionist, who conspired to achieve secession by
force majeure. He rejected Lincoln's call for troops to put down rebellion.
Meanwhile, he called up part of the Missouri State Guard under the command of secessionist officers, and stationed them outside St. Louis. Artillery was secretly provided by the nascent Confederacy.
The goal of this force was to seize the U.S. Arsenal in St. Louis and control the city. However there was a U.S. Regular Army force there, under a fanatical Union officer (Nathaniel Lyon).
Also, St. Louis was predominantly Unionist (and in fact Republican) St. Louis elected the only Republican US Representative from a slave state. This was due to the presence of many German immigrants. Mostly radical refugees from the failed revolution of 1848, they hated slavery. Lyon and Republican leader Frank Blair organized an unofficial pro-Union "Home Guard" in St. Louis.
Lyon determined that the State Guard were plotting rebellion. (He scouted their camp, disguised as an old woman.) So one day he led his Regulars and the Home Guards to the camp and took the entire State Guard force prisoners. While Lyon was marching the prisoners to the arsenal, gunfire broke out and several dozen people were killed.
This almost triggered a secession vote in the legislature in Jefferson City - except that the legislature had delegated that decision to the convention. However Jackson now called up more State Guards, while Lyon marched on Jefferson City. He routed the State Guards and chased out Jackson and his supporters, pursuing them to the far SW of the state.
Meanwhile, a majority of the legislature stayed behind, and reformed the state government. They replaced Jackson as governor, and Missouri was securely in the Union.
Kentucky was a different story. There were no US troops on the ground, and no city with a Republican majority. Governor Magoffin was pro-Southern, though like most Border State men he hoped for a "compromise" to avoid war, i.e. the North and Republicans yielding to Southern demands. He called up state militia under pro-Southern officers and declared the state "neutral".
However, the majority of the state's voters were anti-secession. The US Army stayed out of Kentucky, but Navy Lieutenant William Nelson was sent in to organize a Unionist Home Guard. In mid-1861 elections, Union candidates won overwhelming control of the legislature. Magoffin used every power he had to prevent Kentucky declaring for the Union, but in early September, Confederate forces invaded Kentucky, seizing Columbus on the Mississippi. Union troops then occupied Paducah.
Magoffin tried to demand the withdrawal of both forces, but the legislature instead voted to demand only Confederate withdrawal and request Federal action to expel them. The state militia marched off to join the Confederate army, becoming the "Orphan Brigade". Magoffin clung to office until August 1862.
Ex-Vice President John Breckinridge had been elected US Senator in early 1861. When he was expelled from the Senate, he went South, joined the Confederate Army, and became a major general. (Also the answer to a trivia question: who is the only ex-Vice President that anyone has ever tried to kill, excluding those who became President? Breckinridge had many thousands of Yankees shooting in his direction - at Baton Rouge, Chickamauga, and Newmarket.)
Getting to the What-If... it can't apply to Missouri, because US forces were there already (it was a frontier state, remember).
Kentucky, though... If the CSA had not entered Kentucky... The Union faction was dominant and getting stronger. Jeff Davis endorsed the occupation of Columbus, despite the reaction, because he (and others) were convinced that Kentucky would soon be lost anyway. They were probably right, though I can't figure out how it would happen.
If Kentucky's legislature overrode Magoffin and declared for the Union - then, probably, the Union grabs Columbus first. That's the only major knock-on I can see.