Hannibal Hamlin in the context of "Emancipation Proclamation"

A political campaign is an organized effort which seeks to influence the decision making progress within a specific group. In democracies, political campaigns often refer to electoral campaigns, by which representatives are chosen or referendums are decided. In modern politics, the most high-profile political campaigns are focused on general elections and candidates for head of state or head of government, often a president or prime minister.

A United States presidential election was held on November 6, 1860. The Republican Party ticket of Abraham Lincoln and Hannibal Hamlin emerged victorious.

In 1860, the United States was divided over the issue of slavery. Four major political parties nominated candidates in the 1860 presidential election. Incumbent president James Buchanan, a Democrat, did not seek re-election. The anti-slavery Republican Party nominated Abraham Lincoln, a former one-term Whig Representative from Illinois, for president. Its platform promised not to interfere with slavery in the South, but opposed extension of slavery into the territories. A group of former Whigs and Know Nothings formed the Constitutional Union Party, which sought to avoid disunion by resolving divisions over slavery with some new compromise. The 1860 Constitutional Union Convention put forward former Tennessee Senator John Bell for president. After the 1860 Democratic National Convention adjourned without agreeing on a nominee, a second convention nominated Illinois Senator Stephen A. Douglas as the Democratic presidential candidate. Douglas's support for the concept of popular sovereignty, which called for each territory's settlers to decide locally on the status of slavery, alienated many radical pro-slavery Southern Democrats. With President Buchanan's support, Southern Democrats held their own convention, nominating Vice President John C. Breckinridge of Kentucky for president.

Moderate Republicans were a faction of American politicians within the Republican Party from the party's founding before the American Civil War in 1854 until the end of Reconstruction in the Compromise of 1877. They were known for their loyal support of President Abraham Lincoln's war policies and opposed the more militant stances advocated by the Radical Republicans. According to historian Eric Foner, congressional leaders of the faction were James G. Blaine, John A. Bingham, William P. Fessenden, Lyman Trumbull, and John Sherman. Their constituencies were primarily residents of states outside New England, where Radical Republicanism garnered insufficient support. They included "Conservative Republicans" and the moderate Liberal Republicans, later also known as "Half-Breeds".

During the 1864 United States presidential election, amidst the backdrop of the ongoing Civil War, moderate Republicans supported merging the Republican Party with the War Democrats (Democrats who supported the continuation of the Union war effort) to form the National Union Party alliance. At the Republican National Convention (which operated under the name of the "National Union National Convention" that year), they spearheaded the effort to replace Lincoln's vice president Hannibal Hamlin with Tennessee Democrat Andrew Johnson, acting out of the belief that placing a War Democrat on the presidential ticket would solidify support to ensure Lincoln's re-election.

The 1860 Republican National Convention was a presidential nominating convention that met May 16–18 in Chicago, Illinois. It was held to nominate the Republican Party's candidates for president and vice president in the 1860 election. The convention selected former representative Abraham Lincoln of Illinois for president and Senator Hannibal Hamlin of Maine for vice president.

Entering the 1860 convention, Senator William H. Seward of New York was generally regarded as the front-runner, but Lincoln, Governor Salmon P. Chase of Ohio, former representative Edward Bates of Missouri, and Senator Simon Cameron of Pennsylvania all commanded support from a significant share of delegates. Seward led on the first ballot but fell short of a majority, while Lincoln finished in a strong second place. Cameron's delegates shifted to Lincoln on the second ballot, leaving Lincoln essentially tied with Seward. Lincoln clinched the nomination on the third ballot after consolidating support from more delegates who had backed candidates other than Seward.

Presidential elections were held in the United States on November 8, 1864, near the end of the American Civil War. Incumbent President Abraham Lincoln of the National Union Party easily defeated the Democratic nominee, former General George B. McClellan, by a wide margin of 212–21 in the electoral college, with 55% of the popular vote. For the election, the Republican Party and some Democrats created the National Union Party, especially to attract War Democrats.

Despite some intra-party opposition from Salmon Chase and the Radical Republicans, Lincoln won his party's nomination at the 1864 National Union National Convention. Rather than re-nominate Vice President Hannibal Hamlin, the convention selected Andrew Johnson of Tennessee, a War Democrat, as Lincoln's running mate. John C. Frémont, who had been the Republican nominee in 1856, started to run as the nominee of the new Radical Democratic Party, with War Democrat John Cochrane as Frémont's running mate; the new party criticized Lincoln for being too moderate on the issue of racial equality, but Frémont and Cochrane withdrew from the race in September and their new party dissolved. The Democrats were divided between the Copperheads, who favored immediate peace with the Confederacy, and War Democrats, who supported the war. The 1864 Democratic National Convention nominated McClellan, a War Democrat, but adopted a platform advocating peace with the Confederacy, which McClellan rejected, although his running mate George H. Pendleton wrote it. While the Confederacy seemed to have survival potential in summer 1864, it was visibly collapsing by election day in November.