How is "The Crucible" a struggle of power and manipulation? Are there quotes to support this from main characters?
We can certainly see this dynamic in Reverend Parris. He seeks more authority in the town, more status, and he is both worried to lose what he has and willing to act dishonestly to gain more.
Danforth also is involved in a bid for continued authority through the witch trials. He is not the manipulator of events, but rather is manipulated, yet he clearly voices a strong interest in power.
A good question. This play is a work of power throughout, and of manipulation in various key places. The power is evident everywhere. Look at the very first lines of the play: Parris orders Tituba to leave. Now look at the last act: the community is putting people to death. You can't get more powerful than killing people and having the community go along with it, even think it is right. Now, as far as manipulation, that's more slippery, and it depends on how you are defining the term. Is it an attempt to get people to do something? Then sure—there is persuasion throughout. If it is an attempt to get people to do something they think is wrong, or that is inappropriate, that's more of a judgment call. Abigail tries to manipulate John into restarting their affair, but in other cases, the people believe what they are doing.