Race And Manifest Destiny by Reginald Horsman pg.198

"Georgia had already rejected this solution, and in the cabinet in December 1825 Secretary of State Henry Clay candidly told Barbour why any plan for incorporating individual Indians within white society was not acceptable. Clay, who in his public statements often attacked the ruthlessness involved in American expansion, argued that "it was impossible to civilize Indians; that there never was a full-blooded Indian who took to civilization. It was not in their nature. He believed they were destined to extinction, and, although he would never use or countenance inhumanity towards them, he did not think them, as a race, worth preserving. He considered them as essentially inferior to the Anglo-Saxon race, which were now taking their place on this continent. They were not an improvable breed, and their disappearance from the human family will be no great loss to the world. In point of fact they were rapidly disappearing, and he did not believe that in fifty years from this time there would be any of them left." Over the next twenty years American scientists, supposedly on the basis of empirical evidence, resoundingly endorsed Clay's conclusions."
-Race And Manifest Destiny The Origins of American Racial Anglo-Saxonism by Reginald Horsman pg.198