The latter sentiment arose from President Abraham Lincoln's Emancipation Proclamation of January 1, 1863.  Many Northern whites concluded that the combined policies of emancipation and conscription meant that they would be forced to risk their lives in a war to free black slaves.  In addition, Democratic politicians and newspapers convinced their constituents, including many Irish immigrants, that emancipation would allow the freedmen to move North to take their jobs and marry their daughters.

For months, Democratic associations in New York City had been distributing pamphlets and organizing public rallies that denounced the war, emancipation, blacks, Lincoln, and Republicans in terms of class and race warfare.  Governor Horatio Seymour promised to challenge the draft law in court, arguing that the quotas for Democratic strongholds, including most of New York City, were unfairly higher than for Republican districts.  Other anti-draft voices called for armed resistance, and at a mass meeting on July 4, Seymour warned, "the bloody and treasonable and revolutionary doctrine of public necessity can be proclaimed by a mob as well as by a government."

By then, New York City was virtually undefended, as thousands of Union troops had left in late June in order to defend Pennsylvania against the recent invasion of Confederate commander Robert E. Lee, which culminated in the Battle of Gettysburg (July 1-3).  Since those troops had not returned to New York, the city had only 550 men in eight forts, and no naval ships in the harbor.  Meanwhile, Governor Seymour's legal ploy to stop the law's implementation was unsuccessful, and the draft's lottery began in New York City on Saturday, July 11.  

At 6 a.m. on Monday, July 13, hundreds of the city's white workingmen marched in protest against the draft, carrying placards and banging metal pans.  The crowd grew as the procession wended its way to the provost marshal's office on Third Avenue, where the lottery commenced at 10:30.  A company of volunteer firemen, angry over losing their traditional exemption from conscription, demolished and burned the draft office.  The expanding mob forced an army squadron of 32 soldiers to retreat, and beat Police Superintendent John Kennedy to a bloody mess.  

Demonstrators downed telegraph poles, uprooted train tracks, and fashioned clubs from fence rails.  The anti-draft zealots then went on an arson spree, targeting homes of draft supporters, well-known Republicans, and the wealthy on Fifth Avenue, looting as they went.  Irish Catholic rioters targeted Protestant charities, such as the Magdalene Asylum and Five Points Mission.  By the late afternoon, protesters had entered the city's arsenal, which they burned (killing ten of their own) when the police arrived.  

The rioters also began attacking blacks, shouting racial slurs, and torching homes of poor African Americans on the west side of 30th Street.  In one of the most infamous incidents, a mob burned the Colored Orphan Asylum on west 44th Street, although its 237 children escaped to safety.   The policy of racial extermination escalated during the night:  a black man was lynched and set afire; while waterfront tenements, taverns, and other others buildings populated by black laborers were systematically burned.  Racially mixed couples were especially at risk from the rioters' wrath. 

At Newspaper Row, across from City Hall, Henry Raymond, owner and editor of The New York Times, averted the rioters with Gatling guns, one of which he manned.  The mob, instead, attacked the headquarters of abolitionist Horace Greeley's New York Tribune until forced to flee by the Brooklyn Police.  

On Tuesday, July 14, the rioters again focused on destroying and looting property of the wealthy, including stores such as Brooks Brothers. The protesters assaulted police and soldiers, who represented federal authority, and erected barricades along First and Third Avenues.  The mob continued venting its ferocious fury on blacks, beating them and burning their homes and businesses.  At least 11 black men were brutally murdered during the riot.  Yet, some of the anti-draft protestors, especially the German Americans, broke ranks with rioters and even assisted the police.

Democratic politicians essentially reacted with a policy of appeasement.  Governor Seymour sent representatives to negotiate with the rioters, while addressing a group of protestors as "My friends," and pledging to work for repeal of the draft.  Republicans, on the other hand, called for swift and forceful action.  "Crush the Mob!"  ran The New York Times headline, as Mayor George Opdyke telegraphed Secretary of War Edwin Stanton for federal troops.  Since Robert E. Lee, the invading Confederate commander, had crossed back into Virginia following his defeat at Gettysburg, Stanton was able to dispatch five regiments to New York City.

The federal troops arrived on Wednesday, July 15, as the demonstrators continued attacking blacks, the wealthy, Protestant missions, and Republicans (who were identified with the previous three groups).  Fierce fighting between soldiers and their allies and the rioters lasted until Thursday evening, July 16.  By Friday, 6000 soldiers were dispersed throughout the city, and the situation began returning to normal.  Similar anti-draft riots occurred in other Northern cities during the summer of 1863, but none as massive and destructive as the one in New York City.

Following the riot, President Lincoln appointed General John Dix, a War Democrat, to ensure that the military draft was implemented and that the city remained at peace.  The prosecuting district attorney, Abraham Oakey Hall, and the presiding judge, John Hoffman, both Tammany Hall Democrats, earned praise from all sides for conducting rigorous yet fair trials.  67 of the indicted rioters were convicted, although few received long sentences.  

Meanwhile, Lincoln reduced New York's draft quota by more than half.  The city's Board of Supervisor's, William Tweed's Tammany Hall, and other organizations began hiring military substitutes for the city's workingmen who could not otherwise afford them.  The draft riot caused many blacks to flee the metropolis, resulting in a 20% decline in New York City's African-American population during the Civil War.