In Woman in the Nineteenth Century, Fuller first notes all the ways the words "all men are born free and equal" is made a mockery of in the United States, especially through the institution of slavery. She notes, again alluding to slavery, that what some free men perceive as freedom is the right to "pamper" themselves "through the misery" of other human beings.

Nevertheless, she says the words all men are free are not spoken in vain (are not worthless) because they can still inspire and encourage good people to spread freedom and work to shame the bad into better behavior. As long as the words ring out, she says, the ideal of freedom is held up before people, and, therefore, must spread until everyone is, in fact, free. People are not deaf, she says, and once an idea comes into circulation, it is all but certain it will be eventually enacted. As she puts it:

That, which has once been clearly conceived in the intelligence, must be acted out.

Fuller will go on to argue that because men and women are equal in the eyes of God, they will achieve earthly equality—but only after women give up being dependent on men.

Margaret Fuller explicitly states that the phrase "all men are created equal" is not just a moral law but a divine imperative. This is a smart rhetorical move as it makes it all the more difficult for its opponents to challenge. After all, if a particular maxim is endorsed by God, then who are we to contradict the Almighty? Aside from its rhetorical force, the phrase represents a bright, shining ideal, something at which the women's rights movement should aim.

Fuller doesn't believe that full equality will ever be achieved—at least not outside the legal sphere—but the ideal has an important role to play nonetheless in inspiring women to strive for what's rightfully theirs. Unlike "separate spheres" feminists like Catherine Beecher, Fuller argues that there are no essential differences between men and women, and that therefore the appropriate strategy for attaining women's rights is through the cultivation of self-reliance in both sexes. In this way, the struggle for women's rights will form an intrinsic part of a wider struggle to fulfill the inspiring words of the Declaration of Independence for everyone.