James McPherson writes in Battle Cry of Freedom (1989) that “On all issues but one, antebellum southerners stood for state’s rights and a weak federal government” (p. 78). Yet that one exception –the fugitive slave law– was a principal cause of the coming Civil War and potentially changes one’s view of the war’s meaning. White southerners were repeatedly infuriated by signs of northern resistance to the fugitive slave law. Abolitionists even taunted them by dubbing their efforts to help runaways an “Underground Railroad.” There was essentially a low-grade border war between North and South over this issue that lasted more than a decade and drove the conflict as much as the crisis over the western territories. Not everybody, not even McPherson, sees the impact of the Underground Railroad as looming this large during the antebellum period, but most of us at the House Divided Project do. That is why the first digital classroom we created was about the Underground Railroad. Partly funded by the NEH, this site offers a host of resources, including historic documents, images, interviews with leading scholars, Google Earth field trips, dozens of K-12 lesson plans and many more tools for the classroom. Especially since this is Black History Month, I hope readers of this blog post will use this opportunity to check out or reexamine these resources and post comments below offering feedback. Everything in the House Divided Project is still in what we are calling a draft edition –all can be fixed, improved or changed as we move toward a public launch during the Civil War 150th commemoration (2011-15).