From Lincoln's Second Inaugural Address:
Seven southern states had already seceded, and the conferees battled against time to craft a compromise to protect slavery and thus preserve the union and prevent war. Participants included former President John Tyler, General William Sherman's Catholic stepfather, General Winfield Scott, and Lincoln's future Treasury Secretary, Salmon Chase—and from a room upstairs at the hotel, Lincoln himself. Revelatory and definitive, The Peace That Almost Was demonstrates that slavery was the main issue of the conference—and thus of the war itself—and that no matter the shared faith, family, and friendships of the participants, ultimately no compromise could be reached.
On the occasion corresponding to this four years ago all thoughts were anxiously directed to an impending civil war. All dreaded it, all sought to avert it. While the inaugural address was being delivered from this place, devoted altogether to saving the Union without war, insurgent agents were in the city seeking to destroy it without war—seeking to dissolve the Union and divide effects by negotiation. Both parties deprecated war, but one of them would make war rather than let the nation survive, and the other would accept war rather than let it perish, and the war came.