Pat Nixon was long regarded as the subservient political wife who wanted only to help her husband President Richard Nixon achieve his goals for the nation.

But a new biography portrays the first lady as willful and combative in her relationship with her husband and his top advisers. She waged “a battle to retain control over her responsibilities,” writes Mary C. Brennan in “Pat Nixon: Embattled First Lady,” due out next month from the University Press of Kansas. “She found herself engaged in almost constant warfare with her husband and some of his advisors . . . and she refused to give up without a fight.”...