Consider the following statement: The persistence of racism in both the North and the South lay at the heart of Reconstruction's failure. Agree or disagree, and explain your position

While racism remained a central fact of life throughout the post–Civil War United States, the reasons for the relative success and failure of various Reconstruction policies and practices are extremely complex; oversimplification explains little. In addition, Reconstruction was never intended to eliminate racism. Rather, its primary goal was to reintegrate into the Union all the states that had seceded to form the Confederacy. Those states were placed under military commands and occupied by Union troops for twelve years (the Civil War itself lasted only four years).
One of the key requirements for each state's readmission to the Union was ending slavery, which meant endorsing the Fourteenth Amendment to the US Constitution and rewriting state constitutions to eliminate slavery.
With African Americans free and sometimes becoming property-owners (although many were impoverished), poor whites' resentment sometimes increased. Many scholars have argued that, rather than thinking that persistent racism causing Reconstruction to fail, we can view Reconstruction as actually increasing or intensifying racism.
https://www.britannica.com/event/Reconstruction-United-States-history