Later in 1845, he accepted the presidency of Knox College in Galesburg, Illinois. The school had recently been opened by anti-slavery social reformers who sought a Christian utopia. The school was deeply in debt but, thanks to donations by Charles E. Phelps and J. P. Williston, Blanchard was able to secure financial stability. The Old Main building, now recognized as a National Historic Landmark, was constructed during his tenure. When Senator Stephen A. Douglas assisted with the passage of the Fugitive Slave Act of 1850, Blanchard harshly criticized him in a newspaper article. He would do the same after Douglas' support for the Kansas–Nebraska Act. The two met in Knoxville, Illinois on October 13, 1854 to publicly debate the issues. In 1855, Blanchard went on a lecture circuit of Kentucky with fellow abolitionists Cassius Marcellus Clay and John Gregg Fee.