Some people think libertarians only care about taxes and regulations. But I was asked not long ago, what’s the most important libertarian accomplishment in history? I said, “the abolition of slavery.”

The greatest libertarian crusade in history was the effort to abolish chattel slavery, culminating in the nineteenth-century abolitionist movement and the heroic Underground Railroad. It’s no accident that abolitionism emerged out of the ferment of the Industrial Revolution and the American Revolution.

How could Americans proclaim that “all men are created equal … endowed by their Creator with certain unalienable rights,” without noticing that they themselves were holding other men and women in bondage? They could not, of course. The ideas of the American Revolution — individualism, natural rights and free markets — led logically to agitation for the extension of civil and political rights to those who had been excluded from liberty, as they were from power — notably slaves, serfs and women. As the great English scholar Samuel Johnson wrote in 1775, “How is it that we hear the loudest yelps for liberty among the drivers of Negroes?”

The world’s first antislavery society was founded in Philadelphia that same year. Thomas Jefferson owned slaves, yet he included a passionate condemnation of slavery in his draft of the Declaration of Independence the following year: “[King George] has waged cruel war against human nature itself, violating its most sacred rights of life and liberty in the persons of a distant people who never offended him.” The Continental Congress deleted that passage, but Americans lived uneasily with the obvious contradiction between their commitment to individual rights and the institution of slavery.

As the idea of liberty spread, slavery and serfdom came under attack throughout the Western world. During the British debate over the idea of compensating slaveholders for the loss of their “property,” the libertarian Benjamin Pearson replied that he had “thought it was the slaves who should have been compensated.”

In the United States, the abolitionist movement was naturally led by libertarians. Leading abolitionists called slavery “man stealing,” in that it sought to deny self-ownership and steal a man’s very self. Their arguments paralleled those of John Locke and the libertarian agitators known as the Levellers. William Lloyd Garrison wrote that his goal was not just the abolition of slavery but “the emancipation of our whole race from the dominion of man, from the thraldom of self, from the government of brute force.”

Frederick Douglass likewise made his arguments for abolition in the terms of classical liberalism and libertarianism: self-ownership and natural rights. After the Civil War, he continued his fight for equal freedom, campaigning against Southern states’ efforts to avoid following the new constitutional amendments. And he applied his belief in liberty and equal rights universally: He backed women’s suffrage, saying “we hold woman to be justly entitled to all we claim for man.” He defended Chinese immigrants, pointing out that there are “no rights of race superior to the rights of humanity.” In Great Britain he joined campaigns for free trade and Irish freedom.

Just as a better understanding of natural rights was developed during the American struggle against specific injustices suffered by the colonies, the feminist and abolitionist Angelina Grimké noted in an 1837 letter, “I have found the Anti-Slavery cause to be the high school of morals in our land — the school in which human rights are more fully investigated, and better understood and taught, than in any other.”

Racism is an age-old problem, but it clearly clashes with the universal ethics of libertarianism and the equal natural rights of all men and women. As Ayn Rand pointed out in her 1963 essay “Racism,”

Racism is the lowest, most crudely primitive form of collectivism. It is the notion of ascribing moral, social or political significance to a man’s genetic lineage … which means, in practice, that a man is to be judged, not by his own character and actions, but by the characters and actions of a collective of ancestors.

What Locke, Garrison, Douglass and many others were fighting for is the ethical basis of libertarianism, a respect for the dignity and worth of every individual. This is expressed in the philosopher Immanuel Kant’s dictum that each person is to be treated not merely as a means but as an end in himself.

Black history is American history, a story of oppression and liberation rooted in the libertarian idea of individual rights. Much of the progress we have made in the United States has involved extending the promises of the Declaration of Independence — life, liberty and the pursuit of happiness — to more and more people. The emphasis on the individual mind in the Enlightenment, the individualist nature of market capitalism and the demand for individual rights that inspired the American Revolution naturally led people to think more carefully about the nature of the individual and gradually to recognize that the dignity of individual rights should be extended to all.

The struggle for freedom is never finished. Today libertarians work for economic freedom that would mean more growth and more jobs, for the freedom for all families to choose better schools for their children, for an end to the counterproductive war on drugs and for criminal justice reform. Respect for the dignity of each person is the foundation of moral and social progress.