How do you celebrate Independence Day? A cookout? Maybe take the kids to a parade?

William Lloyd Garrison, the 19th-century abolitionist, had a different idea for how to observe the holiday. Every flag should be either taken down or flown at half-staff, he wrote in his newspaper, The Liberator, and “all signs of exultation, parade and boasting should be studiously suppressed.” The usual rounds of celebratory music, marching and fireworks must be abandoned until “the millions of our oppressed countrymen are emancipated.” In the meantime, the Fourth of July “should be made THE DAY OF DAYS for the overthrow of slavery.”

In our time, July 4 has become detached from the politics of protest. But the history of the United States suggests that this need not — indeed, ought not — be the case.

Garrison borrowed the July 4 protest tradition from a group of black activists in Albany. When slavery was legally abolished in New York on July 4, 1827, they resolved not to celebrate. Instead, they mourned all those who remained in bondage and came out the following day for public reflection on the nation that allowed it. This became a tradition that continued until the Civil War.