Douglas provided no dates or locations for the speeches he claimed Washburne made, and the editors could find no evidence that Washburne delivered any speeches in 1858 pledging to oppose the admission of any additional slave states into the Union.

During the second Lincoln-Douglas Debate, Douglas had made similar allegations about Washburne. He claimed that delegates to “the Rockford Convention on the 30th of August, 1854” nominated Washburne under their platform, which included a resolution “to prohibit the admission of any more slave States into the Union.” It is true that delegates to an anti-Nebraska convention held in Rockford, Illinois on August 30, 1854 passed this resolution, and that the delegates to this convention nominated Washburne as their candidate for Congress. Although copies of Washburne’s acceptance speech at this convention do not appear to be extant, some newspapers reported that he acknowledged the resolutions the delegates passed and voiced his approval “of the principles laid down.”

Throughout the Lincoln-Douglas Debates, Douglas made statements accusing multiple other Republicans of supporting abolitionist or anti-slavery policies. He also misrepresented the Illinois Republican Party platform in an effort to connect Lincoln with abolitionism and the more radical anti-slavery wing of the Illinois Republican Party. During the first Lincoln-Douglas Debate, Douglas read resolutions from what he claimed was the Republican Party’s first convention in Illinois and claimed that Lincoln helped draft the resolutions. In reality, the resolutions Douglas read aloud were from an 1854 Illinois Anti-Nebraska convention that was held in Aurora, Illinois in October 1854 and Lincoln was neither involved in their drafting nor did he attend the convention. Although Lincoln confronted Douglas on this misrepresentation during later debates, Douglas continually elided personal responsibility for these false claims through the fall of 1858.

If Washburne replied to this letter, his response has not been located. He and Lincoln exchanged a number of letters throughout 1858, but the next letter between the two men that has been located after this September 16 letter is dated January 29, 1859. Douglas repeated his claim about Washburne’s opposition to the admission of additional slave states into the Union during the third, fourth, and fifth debates, but not during the sixth and seventh debates. There is no evidence, from newspaper coverage of the remaining Lincoln-Douglas Debates, that Lincoln ever challenged Douglas during the debates regarding this claim.

Illinois voters in the First Congressional District reelected Washburne to the U.S. House of Representatives in 1858, awarding him 69.8 percent of the vote.

In Illinois’s local elections of 1858, Republicans ultimately won a majority of all votes cast in the state, but pro-Douglas Democrats retained control of the Illinois General Assembly and Douglas won reelection to the U.S. Senate. Through the campaign, however, and in particular through his participation in the Lincoln-Douglas Debates, Lincoln gained recognition and respect within the national Republican Party.