All across American Liberal Media and Academia, there are bitter    jeremiads against Americans opposed to mass migration. Liberals are waging a concerted and relentless assault on Americans opposed to open borders; calling them ignorant, racist Yahoos and troglodytes.   Was and is America a racist society? Yes.    But History itself teaches all living Americans that the racism never squelched the innate sense of Protestant fair play; upon which the American Experiment was founded.    How do we know that?   For there has never been an American Diaspora because of racism; American Blacks had a chance to return to Africa in the 1820s; the nation of Liberia was seized from Africans, so American Blacks could have a homeland on the African continent, free from American racism. That Diaspora never occurred. Lincoln offered free passage to freed slaves to Africa; Frederick Douglass turned the offer down. Marcus Garvey offered to lead an American Black Diaspora back to Africa in the 1920s;