Differences in Economic Mobility in the USA

The Pew Center on the States has provided a website with an interactive visualization of data on the economic mobility, measured at the level of the state (or region).

People have most opportunity to advance themselves in Maryland, New Jersey and New York, least in Louisiana, Oklahoma and South Carolina. Generally the most mobility is available in the northeast, the least in the old south.

I have been reading about the removal of the Indian nations from the east to Oklahoma in the 1830s, about about the Civil War which ended slavery in the old south, and about the 19th century imposition of Jim Crow laws in the old Confederacy. The map suggests that racial prejudice might be largely responsible for the lack of mobility where mobility is low. There is an obvious correlation with the areas of relative strength and weakness of the political parties.