Isabel Wilkerson : Martin case not first America killing with racial overtones and no arrest . Black men murdered for trying to vote , black towns burned to ground , she says . But while each of the previous cases seems almost lost to memory now , it is the national outpouring of outrage from people of all backgrounds in response to the Trayvon Martin case that could signal the difference between the last century and this one . Wilkerson : Florida has been part of the North and its vigilante-enforced racial caste system . The difference in Trayvon Martin case is people of all backgrounds are outraged , Wilkerson says .
Isabel Wilkerson : Martin case not first America killing with racial overtones and no arrest . Black men murdered for trying to vote , black towns burned to ground , she says . Wilkerson : Florida has been part of the North and its vigilante-enforced racial caste system . The difference in Trayvon Martin case is people of all backgrounds are outraged , Wilkerson says .