Critical analysis of Harlem by Langston Hughes

The question, “What happens to a dream deferred?” appears to be answered with nothing but more questions. But if we analyze each question we get an idea of what the speaker really believes about dreams being postponed.
The “dream” is a goal in life, not just dreams experienced during sleep. The dream is important to the dreamer’s life. But what dream is it exactly? The poem does not choose the dream but leaves it up to the reader. Nevertheless, the speaker’s position is clear that any important dream or goal that must be delayed can have serious negative affects.
As we look at each question we find out what those affects are. With each question the speaker offers a possibility of each negative affect. The first one “Does it dry up like a raisin in the sun”: a raisin is already dry, and as a raisin, it is a good thing, useful and nutritious, but if a raisin is left in the sun to dry up, it becomes hard and impossible to eat; its value sucked out, it no longer serves its useful, nutritional purpose.
The dream or life goal of a human being is central to what makes the human a valuable member of society, but suppose that person with the dream is told he cannot fulfill his goal just yet; he must wait until society changes, until institutions and laws change to allow him to become the doctor, lawyer, professor, or poet that he finds his talent and desires direct him to be.
What if he has to take some other job that he lacks interest in until his environment allows him to attain his goal? What if he has no idea how long it will take? And what if he feels that perhaps in his lifetime that time will never come? What happens then? Surely, his talent will dry up, if he is not allowed to develop it.
If the dream does not dry up, maybe it will “fester like a sore— / And then run.” If you have a sore, you want it to dry up so it will heal, but if it festers and runs, that means it is infected and will take longer to heal. The dream that festers becomes infected with the disease of restlessness and dissatisfaction that may lead to criminal activity, striking back at those who are deferring the dream.
Perhaps a dream put off too long is like meat that had rotted. Dead animal flesh that some people use for food will turn rancid and give off horrible odors if not used within a certain period of time. If the dream is not realized in a timely fashion, it may seem to decay because it dies.
The dream may “crust and sugar over— / Like a syrupy sweet?” If you leave pancake syrup or honey unused for several months, and you go back to fetch the bottle, you might find that there is crusty accumulation on the top of the bottle and the contents are no longer usable. Lack of use had formed that crust, that hard material that is no longer useful because no longer pliable. The dream forced to sit idle hardens into an unusable substance of thoughts that have separated themselves from the goals and formed idle destructive thoughts that are crusted over with despair, doubt, anger, and hatred.
The second stanza is not a question but merely a “maybe” suggestion: maybe the dream-goal just sags like trying to carry something heavy. A heavy load makes one walk slowly, makes one clumsy as he tries to move under the load. The dream not realized may become heavy to bear, because it still weighs on one’s mind with musings like “what might have been,” “if only,” “I guess I’ll never know,” “the one that got away.” All these useless thoughts that dip back into the past weigh heavy on the mind that has had to defer a dream. This sagging under a heavy load might lead to depression and mental lethargy.
The last stanza returns to the question again, but this time instead of simile, the speaker employs metaphor of an explosion. What explodes? Bombs explode and cause great destruction. If all the other possibilities of a deferred dream are bad with some worse than others, then the last possibility is the worst. If the person whose dream is deferred loses all hope, he might “explode” with his despair. He might commit suicide, homicide—or both.
The 13th, 14th, and 15th Amendments to the U.S. Constitution—approved in the post-Civil War era—granted black Americans basic rights as American citizens, as did the Civil Rights Act of 1875. However, court and legislative decisions later emasculated the legal protection of blacks. For example, the U.S. Supreme Court ruled in 1896 (Plessy v. Ferguson) that it was legal to provide "separate but equal" accommodations for passengers of Louisiana's railroads. This ruling set a precedent that led to segregated schools, restaurants, parks, libraries, and so on. 
.......Meanwhile, hate groups inflicted inhuman treatment on innocent blacks, including brutal beatings. Lynchings of innocent blacks were not uncommon. Many so-called "enlightened" or "liberal-minded" Americans looked the other way, including law-enforcement officers, clergymen, politicians, and ordinary Americans. By the mid-20th Century, black frustration with white oppression formed itself into a potent blasting powder. 
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.......In 1951—the year of the poem's publication—frustration characterized the mood of American blacks. The Civil War in the previous century had liberated them from slavery, and federal laws had granted them the right to vote, the right to own property, and so on. However, continuing prejudice against blacks, as well as laws passed since the Civil War, relegated them to second-class citizenship. Consequently, blacks had to attend poorly equipped segregated schools and settle for menial jobs as porters, ditch-diggers, servants, shoeshine boys, and so on. In many states, blacks could not use the same public facilities as whites, including restrooms, restaurants, theaters, and parks. Access to other facilities, such as buses, required them to take a back seat, literally, to whites. By the mid-Twentieth Century, their frustration with inferior status became a powder keg, and the fuse was burning. Hughes well understood what the future held, as he indicates in the last line of the poem.