 Complete the following phrase:  Mason wrote the Fugitive Slave Law of 1850, arguably the most hated and openly-evaded Federal legislation in U.S. history. The whole idea of using popular sovereignty as a means to expand slavery into the Western territories, starting with Kansas, leading to the Kansas-Nebraska Act and the violence of the Bleeding Kansas period, was hatched in Masons Washington boarding house. Mason also was the chair of the ad-hoc Senate committee that investigated 