The respective political party platforms from 1864 offer a taste of the political arguments then swirling around the Northern states. The Democrats insisted their objective was to “preserve the Federal Union and the rights of the States unimpaired.” The party platform declared the war unconstitutional, and demanded that “immediate efforts be made for a cessation of hostilities, with a view of an ultimate convention of the States, or any other peaceable means, to the end that, at the earliest practicable moment, peace may be restored on the basis of the Federal Union of the States.”

Republicans, on the other hand, declared the only peaceable solution was the “unconditional surrender of [the South’s] hostility and a return to their just allegiance to the Constitution and the laws of the United States” and called on the government to “prosecute the war with the utmost possible vigor to the complete suppression of the Rebellion.”

While the Democratic platform was mainly silent on slavery, the Republicans openly declared slavery to be “the cause, and now constitutes the strength of this Rebellion.” They called for a Constitutional amendment prohibiting slavery anywhere in the United States.

The Republicans also endorsed Abraham Lincoln and his policies, including the Emancipation Proclamation, and gave their blessing to recruiting black troops for the Union Army.

Both platforms expressed gratitude toward members of the military and promised to compensate them for injuries—but the Republicans did so early on, while the Democrats finally recognized them toward the end of the party convention. This perceived afterthought was not lost on soldiers and sailors, who voted in droves for the Republicans.

And while the Democrats’ platform—a much more abbreviated document than the Republicans’—mainly railed against the war, the Republicans also:
• Encouraged immigration
• Supported construction of a transcontinental railroad
• Called for a “vigorous and just system of taxation”
• Warned European nations to butt out

The Democrats hoped to capitalize on public disillusion with the war with its “peace plank,” which was the handiwork of Clement Vallandigham, a former Ohio congressman and the leader of the Copperhead faction. He had spent a chunk of the war in Canada after his antiwar views got him into trouble with the law.

But attempts before the war to preserve both the Union and states’ rights had clearly failed. And Vallandigham’s rhetoric to “maintain the Constitution as it is, and the restored Union as it was” ignored the Confederacy’s stated war aim of independence—the Davis administration had no particular desire for a reunion with the North; it just wanted out.

It didn’t help the Democrats that their presidential candidate, Maj. Gen. George McClellan, repudiated the peace plank, widening the chasm between the Copperheads and the War Democrats.

Still, the war was going badly for the Union when the Democrats assembled for their Chicago convention, and as late as the week before they met, Lincoln was convinced the Democrats would win. Had the fortunes of battle not turned as they were leaving Chicago, they might very well have.