'Republican' and 'Democrat' are just names, like 'Whig' and 'Tory'.  The party of Lincoln was called 'Republican', but the philosophy was that of today's 'Democrats'.  The 'Democrats' of Lincoln's day held a pro-slavery, white-superiority belief not consistent with today's Democrats.  What is more interesting is why you and others like you keep bringing it up.  What vague premise are you trying to prove?  Do you think it somehow makes white nationalism more palatable?