James Kirby Martin, et al., eds., America and Its Peoples: A Mosaic in the Making, 3rd ed., vol. 1 (New York: Addison Wesley Longman, Inc., 1997), 457, 460.
Attempts to enforce the new law provoked wholesale opposition. In Congress, a Free Soiler declared that it would be the same as 'murder' to return a fugitive to slavery. Eight northern states attempted to invalidate the law by enacting 'personal liberty' laws that forbade state officials from assisting in the return of runaways and extended the right of jury trial to fugitives. Southerners regarded these attempts to obstruct the return of runaways as a violation of the constitution and federal law.