I'm sure he does.
A good starting point is the 1860 census because it lists both slave and free populations.
Missouri's slave population in 1860 was <10% of their total population which indicates that slavery was NOT a major contributor to Missouri's pre-war economy. Compare that to:
- Over half: SC, MS
- Over 40%: LA, AL, FL, GA
- Over 30%: NC, VA, TX
- Over 20%: AR, TN
- Over 10%: KY, MD
Just noticed the tag message for this in my inbox, Medina.
So, those stats would seem to indicate that Missourians had little reason to keep slavery legal, or to join in the rebellion to keep it as a permanent system.
But, by the 1850s, slavery was being defended (in all the slave states) more for social reasons than economic ones. There's a lot of primary-source material from that period that acknowledged that slavery was an inefficient way to organize labor. There was the truism that you could get more work out of a mule than a slave. Few slaves had any incentive to work efficiently, so most didn't. Their incentive was to avoid punishment. Many resisted slavery by "accidentally" breaking their tools, leaning on the hoe, etc.
But the social system, where the poorest, dumbest, least-educated white man could feel superior to every black man was very important for slave-state whites to maintain, even if they saw no economic benefit from the system.
You might find this interesting.

You can see where most of Missouri's slaves were--along the Missouri River.