My friend has been telling me the Civil War started because northern whites were getting sick of former slaves migrating north, so they became militarized. Is there any truth to this

by obvom

Thank you all in advance.

Obligatory-Reference

You can find some excellent answers about this in the wiki.

I especially like this answer from /u/Georgy_K_Zhukov

TL;DR: Your friend is almost as wrong as wrong can be.