More than one political analyst has likened the 2004 election to the contest 140 years ago that pitted another quintessentially civilian Republican commander-in-chief against a Democratic challenger known for his military accomplishments: Abraham Lincoln and former General George B. McClellan.

Eerily presaging this year’s controversies, voters in 1864 pondered: Was the president’s war a folly? Were casualties unacceptably high? Did the military veteran-turned-candidate qualify as a genuine hero or did he exaggerate his record?

Lincoln’s response is worth recalling – and replicating. He urged that Union soldiers in the field – the men placing their lives on the line – be encouraged to vote, and that their ballots be counted separately. Though opponents assailed him as a tyrant, Lincoln was prepared to step aside if the soldiers’ votes threw the outcome to the opposition.

Politically, it was a high-risk strategy. Though the Army had furloughed some enlisted men to participate in off-year elections the previous fall, when Lincoln’s Republicans fared well, there was no guarantee that troops would not seize the chance to elect a pro-peace president committed to ending the war and sending them home. Besides, McClellan had been highly popular with his men during his two stints as their commander.

Justly famous for whipping ragtag volunteers into spruce, proud armies, the dashing general inspired soldiers simply by riding past them in review. And the notoriously procrastinating McClellan earned particular gratitude by keeping his men out of battle as often as possible.

Lincoln was by no means certain that soldiers – many furious that he had changed his war aims from that of preserving the Union to emancipating slaves – would support him. As late as mid-October, by his own calculations – shades of our modern red state-blue state standoff – Lincoln believed the race was dead even.

Further complicating the picture, election laws were even more inconsistent in 1864 than they are today. Some states allowed their soldiers to vote by absentee, or even proxy, ballot, but not crucial Massachusetts, Rhode Island, New Jersey, California, Delaware, or the electoral vote-rich battlegrounds of Indiana and Illinois. Lincoln wanted soldiers who qualified to be furloughed in time to return home and cast ballots that would count in the vital race for electors.

The final results in Illinois and Indiana, he believed, might hang in the balance. But he also ordered that polling places be set up in camp for the vast majority who remained in the field, and would otherwise remain disenfranchised and unheard. The men in harm’s way, Lincoln believed, deserved what amounted to an independent referendum.

The results more than vindicated him. The military voted nearly 78% in the president’s favor – 116,887 to 33,748. Marveled one happy officer: “The soldiers are quite as dangerous to Rebels in the rear as in front.” To Lincoln, the vote proved that despite three years of war, “we are not exhausted.”

But can the same be said of American troops in Iraq? Should we not find out? Modern absentee ballot laws ensure they can vote. But there is no guarantee we will learn whom they preferred.

Like the soldiers of the Civil War, they are fighting in a conflict whose original rationale has shifted. Both President Bush and Senator Kerry – not to mention the millions of civilians in whose name the troops daily risk their lives – owe them the chance to be heard. We would honor them, and inform ourselves, if their ballots were tabulated separately, as they were in 1864.

As General Ulysses S. Grant put it that year: “They have as much right to demand that their votes shall be counted, in the choice of their rulers, as those citizens, who remain at home; Nay, more, for they have sacrificed more for their country.”

Mr. Holzer is co-chairman of the Abraham Lincoln Bicentennial Commission.