We cannot change history, but we can explore different courses it might have taken.

We can learn from counterfactual history perhaps as much as actual history.

Imagine Booth had not shot Lincoln.

Lincoln died at a crux of history. He had won the war, but it remained to win the peace.

We did not win the peace. Reconstruction was largely a failure. Victory was followed swiftly by the Black Codes and the violence of the Ku Klux Klan, a combination rightly called "slavery by another name."

Yet, we should not forget that, for most Southern whites, the aftermath of the war was not much better. Longer term, the South was an economic backwater for both Black and white, whereas there was tremendous growth up North and out West.

How would Lincoln have dealt with these postwar divisions?

We know his sentiments. In his second inaugural address just one month before victory and his own death, he entreated the nation to have "malice toward none, and charity for all; to bind up the nation's wounds; to strive to achieve a just and lasting peace."

As always, the best way to bridge and close a divide, is to find common ground. And common ground there was ... unfortunately, in the form of total postwar devastation that both races endured.

A major national project to rebuild the South would have benefitted both races.

There is an historical example, yet for Lincoln, it lay in the future. A Marshall Plan for the South would have addressed Southern devastation that equaled that in Europe in 1945.

If only the future could inform the past.

Devastation of the South was total. An aid to Union General Sherman wrote "where our footsteps pass, fire, ashes and desolation follow." Union General Sheridan's campaign in the Shenandoah Valley is referred to as "The Burning."

There was no capital to finance a recovery. Wealthy Southerners had purchased Confederate securities which were now worthless.

In the North, however, the war brought not only victory, but explosive prosperity. Per capita wealth doubled from the 1860 to the 1870 census, according to historians Morrison and Commager. The North could have rebuilt the South.

Assistance was sorely needed. The Southern economy had been shattered. Its recovery was anemic. Its predominantly agrarian economy persisted, still with cotton as king. Even so, as late as 1870, the Virginia cotton crop was just one-third of its pre-war volume, corn and wheat one-half.

Lincoln had preserved the Union, yet it was a house divided on its North-South axis, as much as it was racially divided in the South.

A Marshal Plan would have addressed both divisions. The Marshall Plan after World War II provided aid to friend and foe alike.

Defeated Germany received more aid than allied France.

If vanquished white Southerners and newly freed Black slaves had both received assistance, there would have been "a rising tide to lift all boats," in John F. Kennedy's words a century later. When all boats rise, bitterness does not enter the human heart.

A Southern Marshall Plan would have rebuilt a South that was decoupled from the rest of the nation, misunderstood and ill-regarded.

Instead, carpetbaggers from the North preyed on Southern weakness, compounding regional antipathy.

What are the lessons from this historical speculation?

First, government programs are essential to meet dire need. Only with the Marshall Plan did post-war Europe rise again. The tragic counterpoint is the American South without Lincoln.

Second, aid should be extended to everyone in genuine need — friend and foe, the defeated as well as the victors.

These lessons are relevant today. Was the American left's massive trillion-dollar Build Back Better social justice campaign consistent with them? It was designed to channel aid almost exclusively to historically oppressed Black people and massive overshot any measure of genuine need.

The Marshall Plan that revived Europe cost only $13 billion, or about $115 billion in today's dollars.

In contrast, there was no assistance even contemplated for the predominantly white industrial heartland, which was devastated in the early 21st century. A 2016 MIT-Harvard study found that, from 1999 to 2011, the nation lost up to 2.4 million jobs to China, predominantly manufacturing jobs in the heartland. That's more jobs than were created in the entire nation during that period.

The human cost was tragic, as revealed in an Economist Magazine article entitled "Illness as Indicator," which documented that the strongest indicator of support in 2016 for Donald Trump, who made China a central campaign issue, was disastrous public health metrics.

Tragically, the North did not rebuild the South as it could have, and as Lincoln likely would have. Yet, we cannot change that history. We can only avoid repeating its mistakes. On the positive side, we can be inspired by what might have been had Lincoln lived.

Red Jahncke is president of The Townsend Group Intl, LLC, based in Connecticut. He is a regular contributor.