King states that America has defaulted in the promise that it made to African Americans. He tells us that African Americans were promised that they were going to receive the same rights and privileges that other groups enjoyed. However, he argues that this is not the case, as African Americans have suffered much more discrimination and hardship than other groups.
The language that King employs is particularly effective as it presents this promise in financial terms. He compares them to a cheque that has not worked. This language not only clarifies his meaning, but it also helps the reader better understand the feelings of the African American population.