As Abraham Lincoln had an Army of the Potomac that looked inert under Gen. George McClellan, Obama has an Economy stalled and troubled, and two wars, one now branded as the nation’s longest, its outcome never more uncertain.

Abraham LincolnAlexander Gardner Abraham Lincoln

Where to advance? Where to retreat? Who to fire? Who to hire? The general of the one conflict, in Afghanistan, has been removed, as was McClellan by an impatient president. But the other campaign, the one to resurrect an economy ruined by debt and unregulated greed, seems intractable.

The country is divided, with no common purpose other than revulsion at things disliked — oil in the ocean, Wall Street in its excess — and, for diversion, a man who storms a hot-dog-eating contest.

What divides us now, blue states and red states, the recovering cities and the never-going-to-rebound cities, is nothing, of course, compared to that 1860s war over America’s original sin.

But history always leaves some valuable clues along the roadside. In Afghanistan, the way out has to begin with the general who is now way in, perhaps the only public figure to emerge from the Bush years with his reputation for competence intact. Gen. David H. Petraeus took command over the 4th of July holiday, saying “we are in this to win.”

The general’s words barely made the mid-sections of the newspapers and back ends of the broadcasts during a news-free period. At the same time, in small type and with few mentions, were the latest to die in that war — Kristopher Chapleau, 101st Airborne, from LaGrange, Ky.; Ryan Grady, 86th Infantry, from Bristow, Okla.; and David Wisnieski, Air Force, from Moville, Iowa.

In case any of us have forgotten, these dead soldiers seem to hail disproportionately from rural and small-town America. Their friends and family might ask Michael Steele, the Republican Party chairman, if they died in “a war of Obama’s choosing,” as he said. If the Democratic party leader had said such a thing publicly, he would be called a coward, or even a traitor, by the loudest voices in Steele’s party.

The more level-headed critics look at Afghanistan, which the United States stormed into nine years ago to root out Al Qaeda, and see something closer to a civil and tribal war. The fragile society we are fighting for has yet to show that it’s ready take control of its destiny. And the most violent elements in that region, the religious nihilists whose aim is to deny human nature and love of music, beauty, pleasure — or even something so simple as allowing a girl to attend school — have fled to a lawless region of Pakistan.

General David H. PetraeusMajid Saeedi/Getty Images Gen. David H. Petraeus at a ceremony in Kabul on July 4, 2010.

If Petraeus is to become Obama’s Ulysses S. Grant, he needs something to fight, something visible and full-dimensional. There is no standing army among the cave-dwelling and night-moving Taliban.

Obama has set a deadline, subject to much debate, to begin withdrawing troops by July of next year. But a mere passing of calendar months cannot do for the people of Afghanistan what they will not do for themselves. A transplant of motivation must take place, something even a highly regarded American general and his army cannot do.

The other big stall, the economic Army of the Potomac, will not respond to deadlines or firing generals. The Republican governing philosophy of a criminal deregulatory environment drove the economy into a ditch. And when they put more than a trillion dollars worth of wars on the credit card, they left future administrations with few options.

The Democratic ideas, guided by a belief that government stimulus would be worth the risk of further running up the deficit, have not sufficiently jolted the sick American economy back to life. For a while, it looked like the Obama injections of federal money were working. As of mid-April, the administration was on a pace to create more jobs in a year than Bush created in eight years. The stock market at that time was up 70 percent over 13 months. Overall tax bills were the lowest in 50 years, according to the nonpartisan Tax Foundation.

But then, just as quickly, the economy lost its loft, and Obama could only point to what he prevented, and meekly ask to stay the course. Even if the stimulus averted another Great Depression, that is a tough sell, for the public will never give a leader credit for preventing something from happening.

Job creation has now slowed to a crawl. At the current pace, it could take 10 years just to replace the jobs lost during the recession, lending credence to the idea that the boom years were all a historic aberration; the new normal is bleak.

Over the last decade, two opposing theories have been put in play, and neither has succeeded. Is there a third way? The stalled economy, kicked by both parties, has to move, on its own force. But how? Obama still hasn’t found the source.