The Michigan Personal Freedom Act of 1855 defied the hated fugitive slave act and helped nullify it in practice.
In 1850, Congress passed the Fugitive Slave Act, denying any semblance of due process to people accused of being an escaped slave, and legally forcing everyday people to help slave catchers.
In response, the state enacted the Michigan Personal Freedom Act. The 1855 law guaranteed that anybody accused of being a runaway slave would receive, “all the benefits of the writ of habeas corpus and of trial by jury” even though the federal slavery law specifically prohibited this.
The Michigan law also banned the use of state or local jails for holding an accused fugitive slave, and made it illegal for Michigan sheriffs to detain accused fugitives. This was a big problem for slave catchers. There weren’t any federal prisons for them to use, and the limited manpower available to help with rendition put a big roadblock in front of the entire rendition process.
Finally, it made it a crime punishable by up to five years in prison to “maliciously seize any free person entitled to freedom, with intent to have such person held in slavery.” This certainly created a chilling effect on the runaway slave catching business in Michigan.
Additionally, with public sympathy solidly on the side of runaways, juries were highly unlikely to find in a slaveowner’s favor.
That, of course, was by design. The whole point of the Personal Freedom Act was to nullify the Fugitive Slave Act in Michigan by making it unenforceable in practice and effect.