Editor's note: Amitai Etzioni is professor of international relations at George Washington University and the author of several books, including "Security First" and "New Common Ground." He was a senior adviser to the Carter White House and has taught at Columbia and Harvard universities and the University of California, Berkeley.
(CNN) -- Many hope that Gen. David Petraeus will save the day in Afghanistan, following what they see as his great success in Iraq. His appointment has been met with nearly unqualified praise.
Rep. John Kline of Minnesota said he was confident that Petraeus "has proven his leadership in Iraq and is extremely well-qualified for this job." Sen. John McCain, speaking for himself as well as Sens. Lindsey Graham and Joe Lieberman, said, "We think there is no one more qualified or more outstanding a leader than Gen. Petraeus to achieve a successful conclusion of the Afghan conflict."
When you meet him, it is easy to see why he is so popular. He is well-educated, West Point and Princeton doctorates; politically savvy, no nasty quotes in Rolling Stone or anywhere else; and very personable.
So it distresses me, but I feel feel honor-bound to point out that the Iraq he left behind is in shambles; that he is not applying what worked in Iraq to Afghanistan; and that the challenges there are much more daunting than in Iraq.
The Bush administration hoped to turn Iraq into a shining democracy that would "flip" the Middle East. It was going to be one more major step in the neocon march toward the end of history, a point at which all nations would become free nations -- that is, just like us.
Instead, we see in Iraq a government that is deadlocked. A country torn by ethnic tensions that could turn into civil war at any moment, especially likely after August 31, when we finish withdrawing our combat troops. A public that yearns for the law and order and services that Saddam Hussein's government provided. After seven years and many billions of U.S. dollars, most Iraqis still cannot get more than a few hours of electricity a day, even in the sweltering summer. And many other government services are below what they used to be in 2003. Corruption is rampant.
Last, but not least, Iraq used to be a major military force that countervailed Iran. Now it is a very weak sister, and Iran has considerable influence over the Shia majority in Iraq.
Much of this was not Petraeus' doing, but he did little to correct the mess. His much-celebrated success was to reduce the violence from the 2005-2006 levels, but it is on the rise again. Even al Qaeda is gaining. And it is far from clear how much of the security gains that were achieved are because of the surge, now imitated in Afghanistan, compared with a deal Petraeus made with a major Sunni group that turned it from insurgents to our supporters.
In Afghanistan, Petraeus is trying to win the hearts and minds of the population, not by buying a few chiefs, but by building an "effective and legitimate" government, leading with a drive to curb corruption -- a drive that is faltering. Afghanistan is the world's second-most corrupt nation. And the general is working with the central government, which many of the very tribal, locally oriented Afghans despise and reject.
Petraeus is also hobbled because Afghanistan's insurgents have a major source of support and bases in a neighboring country, Pakistan, that they did not have in Iraq.
In both countries, U.S. policy has been unrealistic and vastly too ambiguous. President Obama initially aimed to "dismantle, disrupt and defeat al Qaeda" in Afghanistan. Period. This goal has been accomplished. Fewer than 100 members of al Qaeda are left in Afghanistan -- fewer than in Yemen and Somalia. The Taliban have no designs on us beyond making us leave.
But somehow, the mission got expanded to include nation building, a very costly, long and failure-prone task. Most recently, it also expanded to include preventing India and Pakistan from coming to blows over who will have more influence in the post-U.S. Afghanistan. In Iraq, we started by seeking to remove that nation's weapons of mass destruction. When we found out that our work was done -- because no such weapons were there -- instead of going home, we decided to democratize that nation on the run. Another mission impossible.
No wonder even our best generals cannot win. Petraeus' reputation will be but one of many, although far from the most tragic, losses brought about by Washington's stunning inability to realize the limits of our capacity to shape the world in our image.
The opinions in this commentary are solely those of Amitai Etzioni.