America's military "surge" in Afghanistan shares the same goal as the first one in Iraq nearly three years ago: to stem runaway violence. But the comparisons quickly fade from there.
The U.S. reinforcements that poured into the Baghdad region in early 2007 had clearer objectives, better-trained local forces as allies and an established supply network to keep them moving. What awaits the 30,000 additional soldiers in Afghanistan is much more a work in progress.
As Davood Moradian, senior adviser to the Afghan Ministry of Foreign Affairs, cautioned: "Afghanistan is not Iraq. Therefore, we have to be very careful about that."
The differences begin with what the Pentagon seeks to accomplish.
In Iraq, it was rather straightforward: to use the extra military muscle of 20,000 troops to calm a sectarian bloodbath between Sunni insurgents and the majority Shiites who took command of Iraq's politics and security forces after the fall of Saddam Hussein. Then-President Bush described it as giving some "breathing space" for the Baghdad government.
The timing for the Iraqi surge also worked in America's favor. Sunni tribes in western Anbar province - where the surge began - were turning against al Qaeda in Iraq and other insurgent groups that used Anbar as a base. Sunnis also had been driven out of many mixed areas of Baghdad and were feeling vulnerable.
To the tribal sheiks, the real danger was being sidelined by Iraq's new Shiite leadership and its cozy links to Shiite giant Iran. The surge gave the tribal militias a chance to become deputized as allies by the U.S. military and win some serious political chits with Washington for their help.
In Fallujah, a Sunni food store owner Ziyad Abbas recalls people applauding the joint patrols of American soldiers and Sunni tribal militiamen. "More troops in the street meant more chances to give them information and tips and that was very difficult when they were kept in their camps," said Abbas.
In Afghanistan, it's less clear how the Pentagon hopes to deal with this dual mission of battling the Taliban and trying to win over civilians.
Much of the surge doctrine is built on the premise that the Taliban is a natural host for al Qaeda - the Taliban refused to turn over Osama bin Laden after the Sept. 11, 2001 attacks. But al Qaeda has morphed over the years into more of a franchised brand of jihadi with groups linked together by the Web - and less in need of a physical base of operations and recruitment. The links between al Qaeda and the Taliban are no longer as apparent.
It is also harder to make deals with the Taliban because - unlike Iraq's rival groups - it has little vested interest in affairs of state and finance.
The Taliban has its own turf: the ethnic Pashtun areas in southern Afghanistan where it can flex its ultra-strict interpretation of Islam and take cuts from drug and smuggling trades. Taliban ideology has very little sway over other areas and ethnic groups in Afghanistan.
The top U.S. commander in Afghanistan, Gen. Stanley McChrystal, said the Afghan government and its Western military backers should seek to offer the Taliban a way to rejoin the country with "dignity."
That's assuming, however, a vision of nationhood that is similar to the West. Afghanistan's central authorities have never held firm control of the entire country, which in reality is a patchwork of fiefdoms and ethnic enclaves that give main allegiance to local chiefs and warlords. The Kabul government of President Hamid Karzai has full sway over only a portion of the country.
"There isn't the sense of strong, central government as in Iraq," said Ayesha Khan, an expert on Afghanistan for the London-based Royal Institute of International Affairs (a.k.a. Chatham House). "The tribal and fragmented nature of Afghanistan makes it quite a different place from a military point of view."
The level of help from local forces is another complication for the new surge.
Iraqi military forces - built from scratch after the U.S.-led invasion in 2003 - have a blemished record. But they have received extensive training and generous funding in recent years. The Iraq surge was one of their first major tests as side-by-side partners with America, and they generally came through in crucial roles such as neighborhood patrols and intelligence gathering.
Afghanistan's military trails well behind. Training Afghan forces has been slowed by problems such as lack of equipment and weapons and a high rate of illiteracy which makes instruction manuals useless. Reports of Afghan soldiers going AWOL are common.
Sen. Carl Levin, chairman of the Senate Armed Services Committee, said Wednesday that the ratio of U.S. troops to Afghan soldiers was 5-to-1 in the Taliban stronghold of Helmand province.
"Doubling the number of U.S. troops in the south will only worsen a ratio under which our forces already are matched up with fewer Afghan troops than they can and should partner with," Levin said at the opening statement at a committee hearing.
Although details of the surge have not been announced, the strong likelihood is strategic deployments in rugged Helmand province and smaller units to reinforce Canadian-led forces in and around Kandahar, the second-largest city in Afghanistan.
This presents some serious problems with basic logistics.
Iraq's surge was incorporated into a well-established military supply network in and around Baghdad to funnel food, fuel and ammunition to the troops. In Helmand, the added troops will compound an already difficult effort to shelter and supply the forces. The region has only one major airfield and road transport is slow on rutted roads that are also vulnerable to attack.
The numbers will be roughly even. There were more than 166,000 U.S. soldiers in Iraq at the height of the surge in late 2007. The Afghan surge will increase American troop strength to about 100,000 alongside at least 40,000 allied forces. NATO Secretary-General Anders Fogh Rasmussen said he expected allies to bring more than 5,000 additional troops.
In Washington, Defense Secretary Robert Gates tried to sell a war-weary Congress on the merits of the Afghanistan surge and the $30 billion price tag. It hasn't been lost on skeptics that his boss, President Barack Obama, was highly critical of Bush's strategies in Iraq.
"This is the second surge I've been up here defending," Gates said.