The past decade has seen an alarming rollback of the voter protections erected by the Voting Rights Act of 1965. Policing access to the ballot based on race is rightly understood as an expression of white supremacy. Time and again, lawmakers have revealed that new voter restrictions are aimed at reducing the voting power of blacks and other minorities. What is less understood is how restrictions on black voting helped to create the very idea of whiteness.

Although many today consider race to be an immutable characteristic, that wasn’t always the case. Before the 17th century, whiteness didn’t even exist as a racial category. It emerged for the worst of reasons: slave-owning politicians invented “whiteness” as part of a political strategy intended to restrict the voting rights of free black men. Lawmakers subsequently refined “whiteness” by developing a “one-drop rule” — the idea that one drop of African blood would make a person “black.” In other words, race isn’t just connected to voter suppression; black voter suppression created whiteness.

We can see the creation of “whiteness” in the slave-based economies of the English Caribbean. Before 1700, religion was the crucial distinguishing characteristic between slavery and freedom. In the Barbados Slave Code of 1660, the first comprehensive English slave law in the Americas, colonists called themselves “Christians” while enslaved and free Africans were “Negroes.” The term “negro,” from the Spanish “black,” acknowledged the precedent of Spanish slavery that the English imitated.

The word “white,” though, was of little importance.

How and why did slave-owning colonists create whiteness? The answer comes from law books and baptismal records.

Law books show that English colonists (and later, Americans) considered Christianity a prerequisite for political power in the 17th century. Slave-owning planters referred to themselves not as “white” people or “slave owners,” but simply as “Christian” men.

Baptismal records reveal why that practice became problematic. In the 17th century, English slave owners generally forbade enslaved people from becoming Christians. Being a Christian, they reasoned, was a privilege — a sign of freedom and superiority. Furthermore, if slavery was justifiable only for “heathens,” then conversion to Christianity would threaten their legal claim to the labor of enslaved Africans.

Yet enslaved and free Africans recognized that Christian status — along with property ownership — was one of the cornerstones of political authority. Despite intense resistance from most slave owners, dozens and then hundreds of enslaved blacks won baptism in English Protestant churches. Some of these enslaved people gained their freedom either before or after their baptism.

The growth of a free black Christian population was politically threatening to the slave-owning class: It meant that black men could claim their right to vote and hold government office, as any property owning male member of the Church of England could. By the 1690s, black Christian men had attained, or were in the process of attaining, all three of the prerequisites to join the ruling class.

As black men grew closer to political authority, English colonists changed the rules. When enslaved peoples were non-Christian, the colonists used religion to justify oppression. As enslaved and formerly enslaved people converted, the colonists changed the language in their law books to replace the word “Christian” with the word “white.” It was intentional and strategic.

The use of race to oppress became more explicit over time. In 1697, English slave-owners wrote a new law, using the word “white” instead of “Christian.” It declared that “every white Man professing the Christian Religion, the free and natural born Subject of the King of England, or naturalized, who hath attained to the full Age of One and Twenty Year, and hath Ten Acres of Freehold … shall be deemed a Freeholder.” It was the first time that “whiteness” was used to determine voting eligibility.

Twelve years later, lawmakers in Barbados refined their definition of whiteness further. A 1709 law forbade any person “whose original Extract shall be proved to have been from a Negro” from voting or testifying in court. The law marked the first time that a “one-drop rule” was used. The law excluded not only slaves, but all free Christian men with African ancestry, from enfranchisement.

The establishment of the one-drop rule laid a new foundation for slavery and social oppression that made race seem like a natural category — something that was innate.

We are still wrestling with the consequences of these centuries-old decisions. Even as much of the general public still considers race a biological category, history tells us something different. Viewing race as biological obscures the political intentions of the men who created whiteness.

Recognizing the political oppression that lies at the root of whiteness can help us move forward. Instead of deconstructing “whiteness” as a category, it is more helpful to think about how whiteness is mobilized today for specific political circumstances. “White people” were created out of an effort to exclude blacks from political power. Whiteness often still works this way today, not just in politics, but in economics and education. As history shows us, whiteness was never about biology. It was — and remains — about politics.