Perhaps the biggest hurdle to the success of reconstruction was the failure of whites to accept the new position blacks had in this country. why would they have so much difficulty in accepting them?

A lot of reasons. For years, white people had a belief that they were naturally superior instilled in them, because of the nature of African origin in the thirteen colonies. A lot of people, especially in the South where slavery was considered a norm, were convinced that they were simply not good enough to hold high positions in society.