 With the growing support of Anti-Slavery Whigs, Fitz Henry Warren was made secretary of the Whig Party National Executive Committee.Warren was chairman of the Des Moines County delegation to the convention of 1856 that organized the Republican Party and nominated John C. Frémont as the first Republican presidential candidate.In 1861 he was one of the chief editorial writers on the "New York Tribune" and the author of the controversial "On to Richmond" articles after the First Battle of Bull Run.