PORTLAND – Public officials in Washington and Augusta now struggling with seemingly irreconcilable differences between political parties might profit from lessons learned from the leaders who dealt with a deeply divided country in attempting to avoid the Civil War.

The Lincoln-Douglas debates held during the 1858 Senate race in Illinois — two years before the country elected Lincoln president — offered alternative approaches to a polarized electorate to preserve the Union. These candidates sought what former Sen. Olympia Snowe called the “sensible center.”

The candidates debated a single topic: whether slavery should extend into the territories — the vast amount of Western land that had not yet become states.

Lincoln and Douglas portrayed each other as extremists, and yet each actually advanced moderate policies in an attempt to find a middle ground between abolitionists and pro-slavery forces.

The incumbent Douglas served as chairman of the Senate committee on the territories and authored the Kansas-Nebraska Act, which left the decision about slavery up to the settlers in each territory. This legislation acceded to the interests of the Southern states by overturning the Missouri Compromise, which had prohibited slavery in the Northern territories.

Douglas believed he could placate the Southern states by removing the prohibition against slavery in the territories.

But he also thought he could satisfy the Northern states because it was unlikely that settlers of the territories would support slavery. Douglas personally opposed slavery but said he “didn’t care” whether a territory supported or rejected slavery as long as it represented the will of the population.

Douglas made slavery a jurisdictional issue — a decision to be made at the local level. In so doing, he subjugated the controversial issue of slavery to a principle that had wide appeal, known as “popular sovereignty.” Through such an approach, he hoped to preserve the Union, maintain a national Democratic Party and perhaps position himself as its presidential candidate.

In his “House Divided” speech, Lincoln challenged the notion of popular sovereignty by arguing that slavery was not a local issue. The country could not continue as part slave and part free; it would eventually move in one direction or the other.

Lincoln pointed to three distinct events that provided evidence the country was tending toward slavery:

The Kansas-Nebraska Act.

The Supreme Court’s Dred Scott decision, permitting slaveholders to take slaves into territories.

President Buchanan’s support for slavery in Kansas despite majority opposition.

In contrast to Douglas, Lincoln looked upon slavery as a moral issue: “I hate it because of the monstrous injustice of slavery itself.” It undermined democracy by making one person a despot over another and weakened the country’s moral influence in the world.

Lincoln argued that no amount of local preference could make the wrongs of slavery right. He criticized Douglas’ moral indifference as legitimizing slavery and wondered how Douglas could “not care” about the issue that everyone in the country cared so deeply about, one way or the other.

Despite the evils of slavery, Lincoln did not side with the abolitionists but forged a moderate position.

He defined the sensible center as supporting slavery in the Southern states, as stipulated in the U.S. Constitution, while curbing its extension into the territories. He sought to put the public’s mind at rest, knowing that slavery was moving in the direction of extinction, even if it took 100 years.

Today’s public officials are heirs of Douglas when they sidestep controversial issues or subordinate their personal views on controversial issues such as abortion, immigration, same-sex marriage and gun control to those of their constituents.

They follow Douglas when they look to localities rather than the national government as the proper jurisdiction for difficult decisions.

But they are descendants of Lincoln when they take a principled stance and yet propose a moderate course of action.

Lincoln teaches today’s public officials to be principled but practical because he recognized that public opinion constrains leaders to make compromises.

Leaders in a democracy must be responsive to the sentiments of the public, but Lincoln reminds us that public opinion is malleable, and the job of public officials is to persuade — to shape the public mind to move in the right direction.

We know the country did not choose the moderate path on the slavery issue, and within a few years it had plunged into a civil war that threatened to tear the country apart.

We can only hope that our generation of leaders learns from the past, forges a middle ground and works to unite a divided country.

Joseph McDonnell is dean of the College of Management and Human Service at the University of Southern Maine and faculty member in the public policy and management program in the USM Muskie School of Public Service.