 McClellan was nominated by the Democrats to run against Abraham Lincoln in the 1864 U.S. presidential election . Following the example of Winfield Scott , he ran as a U.S. Army general still on active duty ; he did not resign his commission until election day , November 8 , 1864 . He supported continuation of the war and restoration of the Union ( though not the abolition of slavery ) , but the party platform , written by Copperhead Clement Vallandigham of Ohio , was opposed to this position . The platform called for an immediate cessation of hostilities and a negotiated settlement with the Confederacy . McClellan was forced to repudiate the platform , which made his campaign inconsistent and difficult . He also was not helped by the party 's choice for vice president , George H. Pendleton , a peace candidate from Ohio . 
