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What the surge means

Kevin T. Ryan is a retired US brigadier general and senior fellow at Harvard University's Belfer Center for Science and International Affairs.

Q: What is the size of the current U.S. deployments in Iraq?

A: Altogether, there are about 140,000 troops. There are 15 brigade-size combat units in Iraq - 13 Army and 2 Marine which account for about 60,000 of the troops. The remaining troops serve in support units; medical, signal, aviation, transport, maintenance, logistics, etc. Five of the 15 brigades are in Baghdad. Army units change over every 12 months in each rotation and Marine units change out at 7 months. (The difference in tour lengths is a function of the needs and abilities of each service to provide forces to the war.)

Q: How many soldiers are in a U.S. brigade?

A: An Army Brigade Combat team (or brigade) has about 3,500 soldiers assigned, but can also have hundreds more attached for the deployment. The Marine Corps call their version of an Army brigade a Regimental Combat Team. They are slightly larger than Army brigades and number about 5,000 troops each.

Q: Why does the Army keep talking about “brigades” instead of total troop numbers?

A: The Army normally counts its force levels in “brigades” rather than individual troop numbers because the numbers of troops working under a brigade can vary.

Q: Who determines how many units are needed in Iraq?

A: The number of units needed in Iraq is determined by the commander of the Central Command, currently General John Abizaid, and the commander of the Multinational Force-Iraq, General George Casey.

Q: When we talk about a “surge,” what are we really talking about? Are these new troops?

A: Since the end of major combat operations in 2003, the Army and Marine Corps have maintained about 15 brigade-size combat units in Iraq. Under that commitment, the size of the Army and Marine Corps has enabled the services to provide each unit about 14 months recovery for every one year of deployment. Since 2003 the Army has surged combat forces into Iraq three times by delaying the departure of units already in Iraq after their replacement units arrived. This method of increasing the number of troops - temporarily overlapping arriving and departing units - is the only way to increase the number of combat units in Iraq. Each time the surge increased the number of units by 2-3 brigades (7,000-10,500 troops).

Q: How can the 20,000-troop “surge” be accomplished?

A: A surge of 5 brigades and 2 Marine battalions (about 21,500 troops) can be accomplished by a combination of accelerating the arrival of scheduled units and delaying the departure of existing units in Iraq after their replacements arrive. The surge can be sustained into the future only by continuing to overlap units as they switch. The defense department has announced that the overlapping of units will begin in January and be fully achieved by May of this year.

Q: What are the potential benefits of such a “surge?”

A: A surge of 5 brigades into Baghdad will double the number of US combat units in the city. The benefit of a surge of this type would be additional U.S. troops for the “hold” or “presence” mission in Baghdad neighborhoods that have been cleared of insurgents. Adding 2 battalions to the Marine force in Anbar Province increases the combat force there by about 33% from 6 Marine battalions to 8.

Q: What are the risks of such a “surge?”

A: The risks of a surge of this type are realized primarily at the end of the surge when units that have been extended or accelerated must cope with the impact on equipment, personnel, and readiness. Right now some of the units being accelerated into Iraq are from the 3d Infantry Division, which is going to Iraq for the third time in four years. Additionally, overlapping units in Iraq decreases the number of units the US has available for other contingencies around the world should they arise.

Q: Will National Guard units be remobilized to sustain the surge?

A: The Chief of Staff of the Army told Congress in December that continuing the current level of Army deployments will likely require remobilization of Guard and reserve units. Secretary of Defense Gates announced in January that he was changing defense policy to permit the involuntary remobilization of Guard units for up to 12 months. If the surge, which increases deployment levels, is sustained more than a few months it is likely that some National Guard and reserve units which have already been to Iraq will be remobilized.

Q: What is the size of the US Army?

A: The US Army is authorized by Congress to have 512,400 active duty soldiers, 350,000 National Guardsmen, and 205,000 Army Reservists. Currently the active Army has about 508,000 soldiers. Secretary Gates announced in January that he would ask the President and Congress to authorize the active Army to grow to 547,000.

Q: What is a brigade combat team?

A: A brigade combat team (also known as simply a brigade) has about 3,500 troops and consists of 2 combat battalions and various support elements; reconnaissance, intelligence, signal, maintenance, etc.

Q: What is a Stryker Brigade?

A: There are 6 Stryker brigades in the active Army (1 in the National Guard) which differ slightly from brigade combat teams. Stryker brigades are equipped with the General Dynamics-built Stryker wheeled vehicle, have 3 battalions, and have about 3,600-4,000 soldiers.

Q: What is a battalion?

A: A battalion has about 750-1,000 troops and consists of 4 companies and various support elements; signal, maintenance, medical, etc.

Q: What is the size of the Iraqi Army?

A: The Iraqi Army has 134,700 troops. The Army has 10 divisions stationed around the country. Prime Minister Maliki announced that he wants to add about 19,000 troops (or 3 divisions) to the force.

Q: How big is a division in the Iraqi Army? How big is a brigade? How big is a battalion?

A: A division in the Iraqi Army is between 6,000 and 10,000 troops and typically has either 3 or 4 brigades with various support elements. A brigade is about 2,000 troops with typically 3 battalions and support elements. A battalion is about 500 troops.