I think there are three contemporary theories of racism based on academic ideas:

1. Freudian psychology: Racism is unconscious belief systems.

2. Marxism: Racism is class struggle.

3. Social (Postmodern/Structural) Power: Racism is caused by social systems, specifically colonialism.

There is some mixing and matching of these three theories, but this is what we use to understand race.

I've reluctantly fallen into the third camp. "Prejudice" falls into the first camp and is inadequate to understand the persistence of racism in America.