War Democrats in American politics of the 1860s were adherents of the Democratic Party who rejected the Copperheads/Peace Democrats who controlled the party. The War Democrats demanded a more aggressive policy toward the Confederacy and supported the policies of Republican President Abraham Lincoln when the Civil War broke out a few months after his win in the 1860 presidential election.
In the critical state elections in Ohio in 1862, the Republicans and War Democrats formed a Unionist Party. This led to victory over the Democrats led by Copperhead Clement Vallandigham. However it caused trouble for Radical Republican Senator Benjamin Wade's reelection bid. War Democrats opposed Wade's radicalism and Wade refused to make concessions to their point of view. He was narrowly reelected by the legislature.
In 1863 the Ohio gubernatorial campaign drew national attention. Ohio Republicans and War Democrats were dissatisfied with the leadership of Ohio Gov. David Tod and turned to War Democrat John Brough after he made a strongly pro-Union speech in his hometown of Marietta on June 10, 1863. He was elected to the governorship that fall on a pro-Union ticket, partly due to his stronger support than Tod of the anti-slavery direction that the Northern war effort was taking. Brough telegraphed Washington that he had a 100,000 vote margin over Vallandigham. President Abraham Lincoln wired Brough, "Glory to God in the Highest. Ohio has saved the Nation."
1864 presidential campaign 
Recognizing the importance of the War Democrats, the Republican Party changed its name for the national ticket in the 1864 presidential election, held during the Civil War. The National Union Party nominated the incumbent president and "former" Republican Lincoln for president and former War Democrat Andrew Johnson for vice president. As a result many War Democrats could support Lincoln's Civil War policies, while avoiding the "Republican" ticket. While a large number of Republican dissidents had maintained an entity separate from the National Union party leading up to the 1864 election, they withdrew their ticket for fear that splitting the vote would allow the Copperhead Democrats and their "peace at all costs" ticket to possibly win the election. The National Union ticket won 42 of 54 available Senate seats and 149 of 193 available House of Representatives seats.
Following Lincoln's 1865 assassination, Johnson became President. In the 1868 lead up to the first post-Civil War presidential election, President Johnson stood as a candidate for the Democratic Party presidential nomination, though he never finished higher than a distant second in the 22 ballots cast at the Democratic Convention.
Lincoln appointed other War Democrats to high civil and military offices. Some joined the Republican Party, while others remained Democrats.
Prominent War Democrats included:
- Andrew Johnson, the U.S. senator, then military governor of Tennessee who was elected Vice President in 1864 on a ticket with Lincoln, and became President after Lincoln's assassination
- George Bancroft, historian and presidential speech writer
- John Brough, Governor of Ohio
- Benjamin F. Butler, Congressman from Massachusetts; Union general
- John Cochrane (general)
- John Adams Dix, of New York, Buchanan's Secretary of the Treasury, Union general
- Stephen A. Douglas, Senator from Illinois; Democratic Party's northern candidate in the presidential election of 1860, who died a few weeks into the war
- Ulysses S. Grant, storekeeper in Illinois & Union general, later became Republican; elected 18th President of the United States 1869; 1872
- Joseph Holt, Kentucky; Buchanan's Secretary of War; Lincoln's Judge-Advocate General of the Army
- Francis Kernan, Congressman from New York
- Michael Crawford Kerr, 32nd Speaker of the United States House of Representatives from December 6, 1875 to August 19, 1876
- John A. Logan, Congressman from Illinois; Union general
- George B. McClellan, railroad president; Union general; Democratic presidential nominee in 1864
- Joel Parker, Governor of New Jersey
- Edwards Pierrepont, in 1875, he was appointed U.S. Attorney General by President Ulysses S. Grant.
- William Rosecrans, led the Union at Chickamauga and was asked to run with Lincoln as a War Democrat in 1864
- Daniel Sickles, former New York congressman, led III Corps at Gettysburg where he lost a leg
- David Tod, Governor of Ohio
- Edwin M. Stanton, Ohio; Buchanan's Attorney General and Lincoln's Secretary of War
- Jean H. * Baker, Affairs of Party: Political Culture of Northern Democrats in the Mid-nineteenth Century (1983) p 152
- Kenneth B. Shover, "Maverick at Bay: Ben Wade's Senate Re-Election Campaign, 1862-1863," Civil War History (1966) 12#1 pp 23-42.
- John C. Waugh (2001). Reelecting Lincoln: The Battle for the 1864 Presidency. Da Capo Press. p. 14.
- William P. Leeman, "George Bancroft's Civil War: Slavery, Abraham Lincoln, and the Course of History," New England Quarterly (2008) 81#3 pp. 462-488 in JSTOR
- Cowden, Joanna D. "The Politics of Dissent: Civil War Democrats in Connecticut," New England Quarterly (1983) 56#4 pp. 538-554 in JSTOR
- Dell, Christopher. Lincoln and the War Democrats: The grand erosion of conservative tradition (Fairleigh Dickinson University Press, 1975)
- Nevins, Allan. War for the Union (4 vol 1961-40)
- Silbey, Joel H. A Respectable Minority: The Democratic Party in the Civil War Era, 1860-1868 (1977)