The prospect of millions of people being rounded up and forcefully deported would be yet another dark stain on American history, just like slavery, the Trail of Tears, Japanese internment camps or the “Operation Wetback” efforts of the 1950s. A mass deportation plan would be a logistical nightmare and incredibly expensive, too. But this has not and will not detract Republicans, who appear more united on the call to “Send them back!” than on toning down the violent immigration rhetoric.