Power is a central theme in One Flew Over the Cuckoo's Nest, manifesting through the dynamics between Nurse Ratched and the patients, particularly Randle McMurphy. The novel explores the struggle for control within the psychiatric ward, highlighting the oppressive nature of institutional power and the resistance against it. Nurse Ratched embodies the authoritarian regime, using psychological manipulation and subtle tactics to maintain dominance. McMurphy's arrival challenges this power structure, sparking a battle of wills that underscores the novel's exploration of power dynamics.

Nurse Ratched's control is characterized by her ability to manipulate and dominate without overt aggression. Her power lies in her capacity to divide and conquer, preventing the patients from uniting against her. She employs tactics such as misnaming McMurphy, a symbolic act of stripping away his identity and asserting her dominance. McMurphy recognizes this manipulation, comparing it to a personal anecdote:

"It was the lady there that started it, made the mistake. I've known some people inclined to do that. I had this uncle whose name was Hallahan, and he went with a woman once who kept acting like she couldn't remember his name right and calling him Holligan just to get his goat."

The power dynamics extend beyond Nurse Ratched and McMurphy to include the ward's staff. The doctor, ostensibly her superior, is weak and easily manipulated, allowing Nurse Ratched to run the ward unchallenged. The three orderlies, known as the Black Boys, are chosen for their willingness to enforce her cruel orders, reflecting her control over both staff and patients. This hierarchy is evident when the doctor, initially enthusiastic about a carnival idea, quickly retreats under Nurse Ratched's disapproving gaze:

"Oh, there are numerous possibilities," the doctor says, sitting up straight in his chair and really warming to it. "Why, I’ve got a million ideas ..." He talks full steam ahead for another five minutes. You can tell a lot of the ideas are ideas he’s already talked over with McMurphy. He describes games, booths, talks of selling tickets, then stops as suddenly as though the Nurse’s look had hit him right between the eyes. He blinks at her and asks, "What do you think of the idea, Miss Ratched? Of a carnival? Here, on the ward?"

McMurphy's rebellion is a direct challenge to Nurse Ratched's power. Unlike the other patients, who are described as "rabbits" accepting their role in the hierarchy, McMurphy refuses to submit. His acts of defiance, from questioning the ward's rules to organizing a party, disrupt the established order. Harding, a fellow patient, articulates the power struggle:

"This world . . . belongs to the strong, my friend! The ritual of our existence is based on the strong getting stronger by devouring the weak. We must face up to this. No more than right that it should be this way. We must learn to accept it as a law of the natural world."