According to the Kentucky Encyclopedia, the American Party (or Know-Nothings) had about 50,000 followers in Kentucky by 1855. Not all of them were of the sort who were involved directly in the bloody riots of August: many were former Whigs who feared that more immigrants like the Germans and Irish would upset the Compromise of 1850 and bring up the slavery issue again to cause a civil war. They were sure that Henry Clay's defeat in 1844 was due to illegal immigrant voting in key states like New York. John J. Crittenden, Garrett Davis, Robert J. Breckinridge, George D. Prentice, and Charles S. Morehead were all important leaders in Kentucky's American Party. In the election of Humphrey Marshall as the 6th District (Louisville environs) representative to the U.S. House of Representatives, William Preston was defeated -- but he won national acclaim for his courageous conduct during the street-to-street fighting in August 1855. This horrific event in his life led him to abandon the already doomed Whig Party and become a strong advocate for the Democratic Party, leading to rumors of his being appointed the plum appointment of minister to England.
This pledge was excerpted from a speech by Hon. D.C. Littlejohn reproduced in "Liberty Tract No. 13: Extracts from Speeches of Several Members of the New York Legislature, Renouncing and Exposing the Anti-Republican Order of Know-Nothings or American Jesuits. February 1st, 2d, 3d, 5th and 6th, 1855. Printed at the "Banner of Liberty" Office, Middletown, N.Y., 1855," a pamphlet in the Wickliffe-Preston Family Papers, Box 50, University of Kentucky Special Collections and Archives.