“I could speak for the slave. John Brown could fight for the slave. I could live for the slave. John Brown could die for the slave.” So said Frederick Douglass of the revolutionary abolitionist John Brown. At Pottawatomie, this hero of the Second American Revolution also drew the blood of counterrevolutionaries. 170 years ago last month, Brown led the so-called “Pottawatomie Massacre.” Bar far from viewing this episode as some abstract political…