Wide Sargasso Sea investigates the theme of power by looking at such institutions as marriage, empire, and slavery. These institutions are all ways in which a person or a group of people can dominate others. For Antoinette and her mother, marriage is a legal arrangement that results in the loss of their economic freedom. Through characters such as Mr. Mason and the Luttrells, the novel shows how the island colonies provided a rich source of income to England, the seat of imperial power. And racial relations continue to register the effects of slavery, even after it is officially ended in 1833, as the hostility of the Cosways' former slaves attest.
Rochester uses the rhetoric of chastity, legality, and sanity to justify his control over Antoinette and her fortune.
What appears to the white characters as mere laziness or irrational, destructive behavior is actually an expression of protest on the part of the black Caribbean community against continuing economic and political injustices.