Until May 1854, many Northern men and women were opposed to slavery in the abstract, without having witnessed any of its effects. After June 1854, the month when Burns was returned to Virginia, a significant number, perhaps even a majority of well-bred Northern men and women, began to speak about what “must” one day happen. If a man could be “stolen” from the streets of Boston and sent to slavery, even worse things might occur. Therefore, the abolitionist cause began to gain ground in Boston and in the neighboring countryside. The best evidence for this is the anger, then the hatred that many Southerners declared for the “damn Yankees” who thought they knew more about the slaves than the people who possessed them.

On its own, the Anthony Burns case was not sufficient to turn the tide, and the Bostonians might eventually have forgotten. But when coupled with the Kansas-Nebraska Act, signed by President Pierce in the same week that Burns was incarcerated, this was enough to bring many Northerners to a new appreciation of just how malicious the so-called “Slave Power” was.