Lincoln's re-election in 1864 "was closer than either the popular or electoral votes" indicated, and without the soldier vote in six crucial States, Lincoln would have lost to George B. McClellan. The slim margins of Republican victory in most States "were probably due largely to the presence of soldiers as guards and as voters at the polls," and had Illinois, Indiana Maryland, Pennsylvania, Connecticut and New York's votes gone to McClellan, "he would have had a majority in the electoral college despite Lincoln's popular plurality.
Bernhard Thuersam, www.Circa1865.com
Bayonets Secure Lincoln's Re-election
"Throughout the summer [of 1864] the Union prospects were in a decline. Grant's armies, despite repeated reinforcements, made no headway, and the casualty lists from the Wilderness to Cold Harbor mounted alarmingly. Sherman, maneuvering in the mountains of Georgia, seemed totally useless. July and August saw Republican hopes at rock bottom.
Early in July . . . The [Republican] Pennsylvania Governor [Curtin] was "down on things generally," and on the War Department in particular. Already Curtin had told Lincoln that he would not consider himself responsible for raising troops or for carrying elections. Pennsylvania was 80,000 men behind [its quota] in troops and the Governor believed the draft would meet general opposition from Republicans as well as from Democrats.
At the same time [Massachusetts Governor] John Andrew was disgusted with the situation and was hoping to find some means of getting both Lincoln and [John] Fremont to withdraw in favor of a third [Republican] candidate. The consensus seemed to be that the war languished and Lincoln would not or could not bring peace. War-weariness and a desire for peace was everywhere.
[New York Times editor Henry J.] Raymond asked [Simon] Cameron's advice . . . let Lincoln propose to Jeff Davis that both sides disband their armies and stop the war "on the basis of recognizing the supremacy of the constitution" and refer all disputed questions to a convention of all the States! Raymond went to Washington to lay the proposal before the President, but Lincoln did not accept it.
Sherman's victory before Atlanta reinvigorated the Republican campaign. The President wrote to Sherman to let Indiana's soldiers, "or any part of them, go home to vote at the State election." This was, Lincoln explained, in no sense an order. Sherman understood that it was a command. He sent soldiers home, and on election day in October the soldiers gathered at the Indiana polls. The Nineteenth Regiment of Vermont Volunteers voted in Indiana that day, but many a Democrat found his vote challenged. When the votes were counted, [Republican Governor Oliver P.] Morton had been elected by a majority of 22,000.
On that same day the need for Lincoln's aid was illustrated in Pennsylvania. There it was thought not necessary to send the soldiers home. [Governor] Curtin . . . determined to appoint some Democratic commissioners to collect the soldiers' votes. As the commissioners passed through Washington, however, the Democrats among them disappeared, under [Secretary of War Edwin M.] Stanton's orders, into the Old Capitol Prison.
Lincoln conferred with Cameron and [Alexander] McClure and asked [Generals] Meade and Sherman to send 5,000 men to Pennsylvania for the November election. The generals sent 10,000, and Lincoln carried the State by nearly a 6,000 majority, while the soldiers in the field added 14,000 more.
[Illinois Governor Richard Yates] appealed to Lincoln to send troops to vote. It was essential to elect a [Republican] State Senate, three congressional districts depended on the soldiers, and even the Presidential and the State tickets were unsafe without the uniformed voters. Defeat [for the Republicans] in Illinois, added the Governor, would be worse than defeat in the field. Under such pleas the soldiers came, and Lincoln carried his home State by 189,496 to McClellan's 158,730.
[Many] soldiers voted Democratic in their camps only to have their votes switched in the post offices. Without the soldiers New York would have remained in the Democratic column. Maryland's vote was clearly the product of federal bayonets. Ohio was safe for Lincoln, and the election clerks at home merely guessed at the distribution of the army's vote."
(Lincoln and the War Governors, William B. Hesseltine, Alfred A. Knopf, 1955, pp. 376-382)