THE COMPOSITION of Missouri's population has undergone steady change since the Civil War. The changing composition of the state's population has been a determining factor in terms of party structure, i.e., political organization and factionalism. The population changes responsible for the type of party structure in the state have had an equally profound effect on the composition of the two political parties and on their relative strength. Of interest, then, is the amount, locus and causes of political change as it has taken place in Missouri.
The fundamental structure of Missouri politics is a product of geography and population movements. The initial population movement into the state came largely from the Upper South, and was composed of many slaveholders who settled primarily along the rivers and in the more fertile sections of the state adjacent to or near the rivers. Later population movements stemmed in large part from the north, and tended to settle in the less populated sections of the state, in the north- west and southwest corners of the state. Therefore, the areas settled earliest, by Southerners, and which are also the more fertile, tend to be Democratic; and those settled later, by Northerners, and which are largely thin soil sections tend to be Republican.
Exceptions to this generalization are found in some river counties and the western Ozarks section. Many