The acquittal represented a personal and professional triumph for Lincoln, who once rocked the defendant's cradle in New Salem. Lincoln took over the defense after a change of venue and the case moved from Mason to Cass County.
The trial resulted from a nighttime brawl, and the resourceful Lincoln produced an 1857 almanac (the year the incident occurred) to argue that the state's witness could not have seen Armstrong kill the victim. There was no moonlight at the time and he was a long distance from Armstrong, so theoretically he could not see that far in the dark. Lincoln also produced a witness who helped acquit Armstrong.
On August 12, 1858, a few months after the trial, Lincoln appeared in Beardstown to speak as the Republican candidate for the U.S. Senate. He spoke on a platform in the city park, a site marked by a plaque across from the courthouse. His opponent, Stephen Douglas, spoke the next day, and later that month they officially began their famous series of debates.