In the 1920s historical markers were placed at the county lines along the route Lincoln traveled in the eight judicial district. This example is on the border of Piatt and DeWitt counties
By the mid-1850s, Lincoln's caseload focused largely on the competing transportation interests of river barges and railroads. In one prominent 1851 case, he represented the Alton & Sangamon Railroad in a dispute with a shareholder, James A. Barret. Barret had refused to pay the balance on his pledge to the railroad on the grounds that it had changed its originally planned route. Lincoln argued that as a matter of law a corporation is not bound by its original charter when that charter can be amended in the public interest, that the newer route proposed by Alton & Sangamon was superior and less expensive, and that accordingly, the corporation had a right to sue Barret for his delinquent payment. He won this case, and the decision by the Illinois Supreme Court was eventually cited by several other courts throughout the United States.
Another important test of Lincoln's legal expertise was a lawsuit in defense of a tax exemption that the state had granted to the Illinois Central Railroad. McLean County argued that the state had no authority to grant such an exemption, and sought to impose taxes on the railroad notwithstanding. In January 1856, the Illinois Supreme Court delivered its opinion upholding the tax exemption.
Lincoln's most notable criminal trial came in 1858, when he defended William "Duff" Armstrong, who was charged with murder. The case is famous for Lincoln's use of judicial notice, a rare tactic at that time, to show that an eyewitness had lied on the stand. After the witness testified to having seen the crime by moonlight, Lincoln produced a Farmer's Almanac to show that the moon on that date was at such a low angle that it could not have provided enough illumination to see anything clearly. Based on this evidence, Armstrong was acquitted.
Lincoln was involved in more than 5,100 cases in Illinois alone during his 23-year legal practice. Amounting to about one case per business day, many cases involved little more than filing a writ, while others were more substantial and drawn-out. Lincoln and his partners appeared before the Illinois State Supreme Court more than 400 times.
In at least one trial, Lincoln's voir dire included a question to prospective jurors as to whether they were acquainted with counsel for the other side. When a few of them turned out to know the other lawyer, the judge interrupted.
"Mr. Lincoln, you are wasting the time of the court," said the judge. "The fact that a prospective juror knows your opponent does not disqualify him."
"No, Your Honor, I understand that," Lincoln answered. "I'm afraid that some of them might not know him, which would place me at a disadvantage."
Republican politics 1854-1860
Lincoln returned to politics in response to the Kansas-Nebraska Act (1854), which expressly repealed the limits on slavery's extent as determined by the Missouri Compromise (1820). Illinois Democrat Stephen A. Douglas, the most powerful man in the Senate, proposed popular sovereignty as the solution to the slavery impasse, and incorporated it into the Kansas-Nebraska Act. Douglas argued that in a democracy the people should have the right to decide whether or not to allow slavery in their territory, rather than have such a decision imposed on them by Congress.
In a speech against the act, on October 16, 1854, delivered in Peoria, Lincoln first stood out among the other free soil orators of the day:
" [The Act has a] declared indifference, but as I must think, covert real zeal for the spread of slavery, I cannot but hate it. I hate it because of the monstrous injustice of slavery itself. I hate it because it deprives our republican example of its just influence in the world-enables the enemies of free institutions, with plausibility, to taunt us as hypocrites-causes the real friends of freedom to doubt our sincerity, and especially because it forces so many really good men amongst ourselves into an open war with the very fundamental principles of civil liberty-criticizing the Declaration of Independence, and insisting that there is no right principle of action but self-interest.
Drawing on remnants of the old Whig, Free Soil, Liberty and Democratic parties, he was instrumental in forming the new Republican Party. In a stirring campaign, the Republicans carried Illinois in 1854 and elected a senator. Lincoln was the obvious choice, but to keep the new party balanced he allowed the election to go to an ex-Democrat Lyman Trumbull.
In 1857-58, Douglas broke with President Buchanan, leading to a fight for control of the Democratic Party. Some eastern Republicans even favored the reelection of Douglas in 1858, since he had led the opposition to the Lecompton Constitution, which would have admitted Kansas as a slave state. Accepting the Republican nomination for Senate in 1858, Lincoln delivered his famous speech: "'A house divided against itself cannot stand.'(Mark 3:25) I believe this government cannot endure permanently half slave and half free. I do not expect the Union to be dissolved - I do not expect the house to fall - but I do expect it will cease to be divided. It will become all one thing, or all the other." The speech created an evocative image of the danger of disunion caused by the slavery debate, and rallied Republicans across the north.
The 1858 campaign featured the Lincoln-Douglas debates, a nationally famous contest on slavery. Lincoln warned that the "Slave Power" was threatening the values of republicanism, while Douglas emphasized the supremacy of democracy, as set forth in his Freeport Doctrine, which said that local settlers should be free to choose whether to allow slavery or not. Though the Republican legislative candidates won more popular votes, the Democrats won more seats, and the legislature reelected Douglas to the Senate. Nevertheless, Lincoln's eloquence transformed him into a national political star.
During the debates of 1858, the issue of race was often discussed. During a time period when few believed in racial egalitarianism, Stephen Douglas informed thecrowds, "If you desire Negro citizenship… if you desire them to vote on an equality with yourselves… then support Mr. Lincoln and the Black Republican party, who are in favor of the citizenship of the negro." Lincoln countered that he was "not in favor of bringing about in any way the social and political equality of the white and black races." His opposition to slavery was opposition to the Slave Power, though this would change during the course of the Civil War.
On May 9-10, 1860, the Illinois Republican State Convention was held in Decatur. At this convention, Lincoln received his first endorsement to run for the presidency.
Election of 1860
Main article: United States presidential election,