New York City was the bastion of the Northern “Peace Democrats” during the Civil War. NYC voted against Lincoln twice, and its first wartime mayor, Fernando Wood, suggested that NYC secede in 1861. Many New Yorkers strongly opposed the war and President Lincoln.

These tensions flared with the Draft Riots of 1863. The Federal Government called a draft in 1863 but many New Yorkers sought to evade conscription. It started off small. Over the weekend of July 11, 1863, the “Black Jokes”, a volunteer firefighter company, organized a raid against New York City’s Provost General’s office. The goal was to break past the police guards and set fire to the records. It was a small raid on Monday morning, July 13, and concluded without significant injury to the parties involved. But the tiny outbreak of violence in the 19th Ward of uptown Manhattan unexpectedly exploded into a city-wide riot across Manhattan with smaller riots in Brooklyn. At least 105 people died, including many blacks who were lynched by the immigrant mobs.

It ended when Federal troops placed the city under martial law and occupied it for the remaining duration of the war.

The city was almost entirely run by the Democratic Party, supported by the Irish and German immigrant vote. During the Civil War, the Democrats were divided between two rival machines – Tammany Hall and Mozart Hall. Mozart Democrats were radicals and populists prior to the war, and when the war started they immediately joined the anti-war movement – officially called the Peace Democrats but also known as the Copperheads. Tammany joined the War Democrats as part of the Republican-Democratic Union Party.

New York City was connected with the South’s cotton trade, but the Union blockade reduced the shipping to the city and left many longshoremen, who lived nearly hand-to-mouth in good times, with work shortages. Inflation rose faster than wages at the time. Crime and gang activity continued unabated, especially in the Five Points area in downtown.

By early 1863, disillusionment set in among Democrats after several Union defeats on the battlefield. The patriotism after Fort Sumter had long since faded. The lists of fatalities from the battlefields of Antietam and Fredericksburg in 1862 and Chancellorsville in 1863 overshadowed the more important but less reported campaigns and victories on the western front.

The Peace Democrats declared the war unwinnable and called for compromise to recognize Southern sovereignty and victory. The Emancipation Proclamation in January of 1863 incited anger with the abolitionist cause. A call to abolish slavery confirmed Democrats’ worst fears of “Black Republicanism” and immigrant mobs blamed the blacks for the war and rising unemployment.

The chief criticism of the Draft Act was Section 13 which allowed substitution and commutation. Anyone who paid $300 was exempted from service.

The $300 commutation fee was a largely exaggerated proble, but it was a symbol for the anti-war movement, as these things usually are. The Draft was never very effective. It mostly raised money and encouraged others to volunteer for service.

Constant racism helped flare the riots. Just as a sample (and a tame one at that) From the New York Herald editorial, 20 October 1862:

“the Irish and German immigrants to say nothing of native laborers of the white race, must feel enraptured at the prospects of hordes of darkeys overrunning the Northern states and working for half-wages, thus ousting them from employment.”

So a four day riot ensued. Irish fire fighters set fire to the conscription records. Then other Irish gangs and thugs grew emboldened and attacked other targets. Following the successful attack on the weakened authorities, larger mobs formed and the riots began.

The riots over the next four days included many attacks on blacks, with a number getting lynched by mobs. Mobs looted and burned the Colored Orphan Asylum, destroyed street cleaning machines and machinery used at docks, and attacked Republicans and their newspapers, the NY Tribune and the NY Times.

The riots only ended when Union Infantry took over the city. The Peace Democrats have been criticized by many historians for inciting anger through populist and racist demagoguery.

CUNY has an interesting history of the Draft Riots.
Here’s a page with the links to the Civil War Official Records
One of the best histories of the riots is Adrian Cook’s Armies of the Street.