Explain "The Great Lawsuit" by Margaret Fuller.

In "The Great Lawsuit," Margaret Fuller argues that women should have the same freedoms as men. As she puts it:

We would have every arbitrary barrier thrown down. We would have every path laid open to woman as freely as to man.

Fuller develops this argument by putting women's rights in the context of abolishing slavery. She understands the current situation of women's rights in the 1840s in America as related in a way to the injustice of slavery.
She contends that the ideals of equality on which the United States was based and which animated the French Revolution have been badly violated in the US but are nevertheless true. She writes that the growing awareness of injustice toward Native Americans and black slaves has brought attention to the unfair situation women are in:

As men become aware that all men have not had their fair chance, they are inclined to say that no women have had a fair chance.

She notes that women are too often lumped with children, treated as inferior, and denied the property rights that males enjoy. She says that the male might be head of the household but is not head of the woman.
Like Mary Wollstonecraft, Fuller argues that treating women with more dignity would elevate men, bringing everyone to a higher plane:

An improvement in the daughters will best aid the reformation of the sons of this age.

Fuller outlines four kinds of marriage, each progressively better. She argues for three forms of marriage superior to the most common, which is simply each partner in his or her own sphere, performing traditional tasks. Marriages and society thrive when spouses move to the second level and mutually idolize each other, even more when they share intellectual companionship, and are best when they function as religious unions on a "pilgrimage towards a common shrine." Religious unions are the highest form of marriage, because they encompass mutual love and intellectual sharing.
Fuller accepts that men and women are fundamentally different, but the transcendentalist in her makes her an individualist, and she notes that the differences between individuals make it difficult to stereotype the sexes. Since each sex can "cross over" and do each other's tasks, each sex should be treated equally. She writes:

Male and female represent the two sides of the great radical dualism. But, in fact, they are perpetually passing into one another. . . . Nature sends women to battle, and sets Hercules spinning; she enables women to bear immense burdens, cold, and frost; she enables the man, who feels maternal love, to nourish his infant like a mother.

Fuller's writing style can seem flowery and her arguments tame, based around old-fashioned ideals of women representing virtue, Christianity, and an emphasis on marriage. Nevertheless, audiences at the time did not miss the radicalism of her ideas, and we should not either. The idea that "every barrier" to women should be thrown down would have included allowing women to vote and enter the workplace. Many people found these to be frighteningly radical notions that would entirely upend society and lead to chaos. Evoking the French Revolution was also a radical stance: it would be like endorsing the ideals of communism, Karl Marx, and the Russian Revolution today. Although the women's rights Fuller advocated for have become commonplace, to the point we can hardly imagine women not having them—the vote, the right to enter the workplace, companionate marriage between equals—at the time they revealed Fuller as a left-wing radical thinker who wanted full female emancipation.