This weekend, millions of Americans will enjoy the fireworks, but others will take a knee on Independence Day. Why celebrate? In her Pulitzer Prize-winning 1619 Project, Nikole Hannah-Jones argued that the primary purpose of the American Revolution was to promote and preserve slavery. But it’s important to get the history right. In 1775, Virginia’s English Governor, Lord Dunmore, proclaimed that slaves who deserted their American masters would be welcomed into the British army as free citizens. Multitudes did so, and soon Dunmore had a black regiment at his command to quell unrest in the colonies. It was only then, Hannah-Jones’ argument goes, with the prospect of losing their enslaved property, that delegates in...