1864 United States presidential election in the context of "1864 National Union National Convention"

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 National Union Party, commonly known as the Union Party, and sometimes as the Republican-Union coalition, was a wartime coalition of Republicans, War Democrats, and border state Unconditional Unionists that supported the Lincoln administration during the American Civil War. It held the 1864 National Union Convention that nominated Abraham Lincoln for president and Andrew Johnson for vice president in the 1864 United States presidential election. Following Lincoln's assassination, Johnson tried and failed to sustain the Union Party as a vehicle for his presidential ambitions. The coalition did not contest the 1868 elections, but the Republican Party continued to use the Union Republican label throughout the period of Reconstruction.

Abraham Lincoln won the 1860 United States presidential election, polling 180 electoral votes and 53 percent of the popular vote in the free states; opposition to Lincoln was divided, with most Northern Democrats voting for the senior U.S. senator from Illinois Stephen Douglas. Following his inauguration, Lincoln sought support from Douglas Democrats and Southern Unionists for his efforts to preserve the Union. He encouraged the formation of bipartisan Union coalitions in the loyal states that replaced the Republican Party throughout much of the Lower North. Besides allowing voters of diverse pre-war partisan allegiances to act collectively, the Union label served a valuable propaganda purpose by implying the coalition's opponents were dis-unionists.

Andrew Johnson was the 17th president of the United States from April 15, 1865, after the assassination of President Abraham Lincoln, to March 4, 1869. The 17th president, Johnson was a member of the Democratic Party before the Civil War and had been Lincoln's 1864 running mate on the National Union ticket, which was supported by Republicans and War Democrats. Johnson took office as the Civil War came to a close, and his presidency was dominated by the aftermath of the war. As president, Johnson attempted to build his own party of Southerners and conservative Northerners, but he was unable to unite his supporters into a new party. Republican Ulysses S. Grant succeeded Johnson as president.

Johnson, who was himself from Tennessee, favored quick restoration of the seceded states to the Union. He implemented his own form of Presidential Reconstruction – a series of proclamations directing the seceded states to hold conventions and elections to re-form their civil governments. His plans did not give protection to the former slaves, and he came into conflict with the Republican-dominated Congress. When Southern states returned, many of their old leaders passed Black Codes to deprive the freedmen of many civil liberties, congressional Republicans refused to seat legislators from those states and established military districts across the South. Johnson vetoed their bills, and congressional Republicans overrode him, setting a pattern for the remainder of his presidency.

The Miscegenation hoax, taking the form of a pamphlet subtitled The Theory of the Blending of the Races, Applied to the American White Man and Negro, was published by New York World staff in December 1863 as part of an anti-Lincoln Copperhead campaign leading up to the 1864 presidential election. The 72-page piece coined the term miscegenation (from the Latin miscere "to mix" + genus "kind") and was put together by World managing editor David Goodman Croly and reporter George Wakeman.

The work purports to be a sincere advocacy of the virtues of racial mixing, but it is a literary forgery intended to prompt opposition to racial equality, and to blame the Lincoln administration for allegedly supporting this goal. The authors unsuccessfully attempted to trick Lincoln into endorsing the work. The World also featured a hoax about a "Miscegenation Ball" with interracial dancing alleged to have been held at a Republican function in New York City during the campaign.

Presidential elections were held in the United States on November 3, 1868. In the first election of the Reconstruction Era, Republican nominee Ulysses S. Grant defeated Horatio Seymour of the Democratic Party. It was the first presidential election to take place after the conclusion of the American Civil War and the abolition of slavery. It was the first election in which African Americans could vote in the reconstructed Southern states, in accordance with the First Reconstruction Act.

Incumbent president Andrew Johnson had succeeded to the presidency in 1865 following the assassination of Abraham Lincoln, a Republican. Johnson, a War Democrat from Tennessee, had served as Lincoln's running mate in 1864 on the National Union ticket, which was designed to attract Republicans and War Democrats. Upon accession to office, Johnson clashed with the Republican Congress over Reconstruction policies and was impeached and nearly removed from office. Johnson received some support for another term at the 1868 Democratic National Convention, but, after several ballots, the convention nominated Seymour, who had formerly served as Governor of New York. The 1868 Republican National Convention unanimously nominated Grant, who had been the highest-ranking Union general at the end of the Civil War. The Democrats criticized the Republican Reconstruction policies, and "campaigned explicitly on an anti-black, pro-white platform," while Republicans campaigned on Grant's popularity and the Union victory in the Civil War.