This isn't actually his accomplishment, as much as it is the accomplishment of the American people to not discriminate on the basis of race, just as it was the accomplishment of the American people to not discrimination on the basis of Christian denomination in 1960.
By far worst president.
If I had to pick the worst President, I would pick Andrew Johnson; he so botched Reconstruction that the country had to live with the mess for at least the next century. At present, Obama is either #2 or #3; depending on what happens in the next three years, he may overtake James Buchanan, whose egregious errors paved the way for the Civil War--or not, though it isn't much comfort for the country to have been the third-worst rather then the second-worst.
*to not discriminate*
You think guilty white liberals and racist blacks voted for the part-black guy because they didn’t want to discriminate based on race?
I still pick LBJ (for the same reasons you pick Andrew Johnson). His policies drastically changed this country. Of course, it didn't happen overnight. These things take time and nearly 50 years later, we are finally and truly reaping the destruction that LBJ set into motion --and it's compounding.