The U.S. troop surge in Iraq has now ended, with the top general's spokesman confirming to VOA that all the combat troops sent in last year to bolster security efforts have ended their tours of duty and left the country.  But according to the Pentagon there are about 16,000 more U.S. troops in Iraq now than there were before the surge started early last year.  VOA Pentagon Correspondent Al Pessin got out his calculator to try to figure out the discrepancy.

Students of mathematics will tell you there is a traditional approach called Old Math, and there are concepts known as New Math.  But they probably don't know about something that falls into neither category.  That is Pentagon Math.

Before the surge, there were about 132,000 U.S. troops in Iraq.  Now the Pentagon says there are 148,000.  That's a substantial increase, more than 12 percent.  Pentagon Spokesman Bryan Whitman was asked to explain.

"We've always said that we know there are certain capabilities that the United States military is going to have to continue to provide until the Iraqis can establish their own organic ability to do those things - medical, logistics, maintenance, air support," he responded.

So these are support troops, not combat troops, and the support troops are staying - or being replaced by fresh reinforcements - to provide the same capabilities to the increasingly active Iraqi Army and Police.  

Boosting Iraq's Security

The Iraqis have demonstrated considerable combat ability in several recent operations, including the expulsion of insurgent and militia forces from Basra and Mosul.  But they still can not provide all their own logistics support, and they lack air power, the ability to do medical evacuations and other important capabilities.

Indeed, the increased need for support troops was predicted back in February by Lieutenant General Carter Ham, who was the chief of operations for the senior U.S. military staff, when he predicted that about 8,000 of the surge forces would stay after the surge combat troops left.

"It also takes into account, as our forces look to transition from leading to partnering and then to over-watch, the need to retain some key enabling capabilities, to help the Iraqi forces with their capabilities," he explained, "such capabilities as command and control headquarters, logistics, aviation, detainee operations and the like."

In the end, the Pentagon says the extra support troops number about 10,000. 

But there are 16,000 more U.S. troops in Iraq than before the surge.  The Pentagon says some of the other 6,000 extra U.S. troops are in the process of taking over for departing troops, so the overall number should go down by a few thousand in the coming weeks.  But that still leaves at least a couple of thousand troops not exactly accounted for. 

US Troop Withdrawal

The Pentagon spokesman, Bryan Whitman, says some may be leaving in the coming weeks, if their services are not needed by the Iraqis.  In addition, he says U.S. commanders routinely request additional capabilities, such as bomb squads and intelligence units, which results in the deployment of small groups, or even individuals, which can add up over time.

"The onesies and twosies become dozens, and the dozens become a few hundred, and a few hundred become a thousand sometimes," Whitman said.  "It's just the way it does.  Commanders have appetites for capabilities."

And he says commanders are always reluctant to give up capabilities once they have them. 
"It's hard to give up capability.  If you're a commander on the ground and you've got something that's working well, it's always a little bit hard to say, 'Well, we can do with less of this or less of that.'  It's hard, I'm sure," he noted.

Combat Troops vs. Support Troops

The number crunching this week over the post-surge U.S. troop numbers in Iraq, raises a question - when Iraqi leaders call for the withdrawal of U.S. troops by 2010, are they talking about all the troops or just the combat troops?  Or put another way, if the end of the surge left 16,000 troops behind, how many troops would a so-called complete U.S. withdrawal leave behind?

Experts say the Iraqi need for air support and other capabilities will not go away by 2010, and neither will the needs to protect American diplomats and reconstruction teams and to use high-end U.S. military capability to pursue any remaining hard-core terrorists and insurgents.

The Democratic Party's presidential candidate, Barack Obama, also wants U.S. troops out of Iraq in 2010, but he is careful to specify that he's talking about combat troops, as he did during a news conference in Jordan on Tuesday, shortly after ending a visit to Iraq.

"Once we redeploy our combat brigades, we're still going to retain a capability to protect our personnel, to target terrorists and to train Iraqi security forces, if there is political progress," Obama said.

In Pentagon Math, even by a candidate who has pledged to end the war, if you deploy troops and then bring the troops home, you're still likely to have a substantial number of troops remaining.  But no one is saying exactly how many will be, as we used to say in Old Math, 'left over.'