Illinois made major contributions to the Civil War, but Abraham Lincoln and the Northern cause were not universally popular in the state. Antiwar forces were strongest politically in 1862 and early 1863. Union defeats on the battlefield, issuance of the Emancipation Proclamation, and popular resentment of such government actions as the suspension of the writ of habeas corpus combined to give major victories to the antiwar Democrats both in the 1862 state constitutional convention and in the 1863 session of the General Assembly.

Democrats controlled the 1862 con-con, and from that base attempted to neutralize the activities of Republican Gov. Richard Yates. Although the new charter they wrote was defeated by 24,515 votes, the electorate approved by majorities exceeding 150,000 votes a stringent set of laws restricting the rights of free Negroes.

The 1863 General Assembly was controlled by Democrats 13 to 12 in the Senate and 54 to 32 in the House. Only the death of a Democratic senator prevented that body from sending five Peace Democrats to an Armistice Convention in Louisville. The General Assembly attempted to turn control of war spending and appointment of officers over to a three-man committee, and listed 15 grievances against President Lincoln and Governor Yates. When the two houses were in temporary and technical conflict over an adjournment date, Yates prorogued the legislature amid howls of protest from the Democrats.

Battlefield desertions also rose markedly in 1862 and 1863 for Much the same reasons which fostered disillusionment at home. When the war ended Illinois counted 13,046 deserters. Some discouragement Was understandable. Fatalities for the war totaled 34,834, including 900 dead at Andersonville and another 621 dead at other Confederate prisons . More than 13 percent of Illinois forces died, primarily from disease.

The state's leading antiwar newspaper was the Chicago Times. Pro-Southern sentiment was strongest in the southern counties; and serious opponents of the war held a mass meeting in Springfield in 1863, attended by 40,000. Although condemning secession, the peace movement also condemned holding the Union together by force. In addition, many opposed fighting an "abolition" war.

Rumors of Copperhead organizations and activities received wide attention, and some arrests were made. An alleged conspiracy to release the Confederate prisoners at Camp Douglas in 1864 failed to materialize, although investigators claimed up to 140,000 Illinoisans were enrolled in secret pro-Confederate societies. Whatever the actual numbers, Copperheads (real and imaginary) created widespread fear and hostility.

In spite of antiwar activity, the vast majority of Illinoisans were loyal to the Union. The state amid its people willingly sacrificed for the war effort, and provided important ingredients in the mark of victory.