[9] In 1977, MacKinnon graduated from Yale Law School having written a paper on sexual harassment for Professor Thomas I. Emerson arguing that it was a form of sex-based discrimination.

Two years later, Yale University Press published MacKinnon's book, Sexual Harassment of Working Women: A Case of Sex Discrimination (1979), creating the legal claim for sexual harassment as a form of sex discrimination under Title VII of the Civil Rights Act of 1964 and any other sex-discrimination prohibition.

While the plaintiff who went to trial on the facts, Pamela Price, lost, the case established the law: the U.S. Court of Appeals for the Second Circuit recognized that, under the civil rights statute Title IX of the Education Amendments of 1972, schools must have procedures to address sexual harassment as a form of sex discrimination.

[10] In her book, MacKinnon argued that sexual harassment is sex discrimination because the act is a product of, and produces, the social inequality of women to men (see, for example, pp.

In 1986, the U.S. Supreme Court held in Meritor Savings Bank v. Vinson that sexual harassment may violate laws against sex discrimination.

[12] MacKinnon, along with fellow radical feminist writer and activist Andrea Dworkin, tried to change legal approaches to pornography by framing it as a civil rights violation in the form of sex discrimination, and as human trafficking.

As documented by extensive empirical studies, she writes, "Pornography contributes causally to attitudes and behaviors of violence and discrimination which define the treatment and status of half the population".

After the press conference, Dworkin, MacKinnon, Boreman, and Gloria Steinem began discussing the possibility of using federal civil rights law to seek damages from Traynor and the makers of Deep Throat.

[19] MacKinnon and Dworkin continued to discuss civil rights litigation, specifically sex discrimination, as a possible approach to combating pornography.

[citation needed] MacKinnon wrote in the Harvard Civil Rights-Civil Liberties Law Review in 1985: And as you think about the assumption of consent that follows women into pornography, look closely some time for the skinned knees, the bruises, the welts from the whippings, the scratches, the gashes.

Civil libertarians frequently find MacKinnon's theories objectionable (see "Criticism" section), arguing there is no evidence that sexually explicit media encourages or promotes violence against women.

[21] Max Waltman states that empirical evidence (based on changes to obscenity doctrine in Canada) suggests that civil rather than legal remedies may be more effective as a means of discouraging violence against women.

"[23] Furthermore, during a lecture at Oxford University in 2022, MacKinnon continued to express her support for transfeminism and transgender sex equality, and criticized the postmodernism, liberalist anti-stereotyping approach, and anti-trans feminism.

[24] Her lecture, called "A Feminist Defense of Transgender Sex Equality Rights" was subsequently edited and published in the Yale Journal of Law & Feminism in 2023.

MacKinnon argues that the Substantive Approach highlights sexualized misogyny and asserts that understanding gender hierarchy benefits all women.

[30] In 2001, MacKinnon was named co-director of the Lawyers Alliance for Women (LAW) Project, an initiative of Equality Now, an international non-governmental organization.

"[33][34] The fundamental concept is that the requirement to exchange sexual services for survival is a product of sex inequality and a form of violence against women.

This makes articulating silence, perceiving the presence of absence, believing those who have been socially stripped of credibility, critically contextualizing what passes for simple fact, necessary to the epistemology of a politics of the powerless.

"[44] In 1996, Fred R. Shapiro calculated that "Feminism, Marxism, Method, and the State: Toward Feminist Jurisprudence", 8 Signs 635 (1983), was the 96th most cited article in law reviews even though it was published in a non-legal journal.

Sex-positive feminists note that anti-pornography ordinances drafted by MacKinnon and Dworkin called for the removal, censorship, or control over sexually explicit material.

[47] In The Nation, Brown also characterized MacKinnon's Toward a Feminist Theory of the State (1989) as a "profoundly static world view and undemocratic, perhaps even anti-democratic, political sensibility" as well as "flatly dated" and "developed at 'the dawn of feminism's second wave... framed by a political-intellectual context that no longer exists — a male Marxist monopoly on radical social discourse'".