Claim of Right is also passed. 1772 – the Somerset v Stewart judgement found that slavery was unsupported by common law in England and Wales. 1859 – an essay by the philosopher John Stuart Mill, entitled On Liberty, argued for toleration and individuality. "If any opinion is compelled to silence, that opinion may, for aught we can certainly know, be true. To deny this is to assume our own infallibility." 1948 – British representatives attempted to but were prevented from adding a legal framework to the Universal Declaration of Human Rights. (It was not until 1976 that the International Covenant on Civil and Political Rights came into force, giving a legal status to most of the Declaration.) 1958 – Two Concepts of Liberty, by Isaiah Berlin, identified "negative liberty" as an obstacle, as distinct from "positive liberty" which promotes self-mastery and the concepts of freedom. United States According to the 1776 United States Declaration of Independence, all people have a natural right to "life, liberty, and the pursuit of happiness". But this declaration of liberty was troubled from the outset by the institutionalization of legalized Black slavery. Slave owners argued that their liberty was paramount since it involved property, their slaves, and that Blacks had no rights that any White man was obliged to recognize. The Supreme Court, in the Dred Scott decision, upheld this principle. It was not until 1866, following the Civil War, that the US Constitution was amended to extend limited rights to persons of color, and not until 1920 that voting rights were extended to women. By the later half of the 20th century, liberty was expanded further to prohibit government interference with personal choices. In the United States Supreme Court decision Griswold v. Connecticut, Justice William O. Douglas argued that liberties relating to personal relationships, such as marriage, have a unique primacy of place in the hierarchy of freedoms. Jacob M. Appel has summarized this principle: In modern America, various competing ideologies have divergent views about how best to promote liberty. Liberals in the original sense of the word see equality as a necessary component of freedom. Progressives stress freedom from business monopoly as essential. Right-wing libertarians disagree, and see economic and individual freedom as best. The Tea Party movement sees the "big government" as the enemy of freedom. Other major participants in the modern American right-wing libertarian movement include the Libertarian Party, the Free