The Islamic State and interior lines: An argument for the U.S. to go back into Iraq

By Col. Gary Anderson, USMC (Ret.)
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Last month, the Iraqi army and associated Shiite militias were celebrating their capture of the Iraqi city of Tikrit after their fighters, who reportedly outnumbered their Islamic State (ISIS) opponents overwhelmingly, finally captured the city after a prolonged offensive that reportedly cost hundreds of pro-government fighters. This victory was finally enabled only by U.S. bombing which the Iraqis belatedly requested after a month-long delay. Within days the Islamic State fighters opened an offensive about 150 miles to the west against the strategically critical city of Ramadi, surprising Iraqi government troops and a precipitating the panicked departure of civilians. This reverse may seem incongruous to casual followers of the conflict, but it was actually a fairly sophisticated manifestation of the use of interior lines by an outnumbered combatant.

Throughout history, nations have found themselves in multi-front wars. When this happens, their sole advantage is in the fact that they can move forces from front to front fairly quickly to deal with the most immediate enemy threat, and then shift those forces to deal with the next threat faster than the enemies can move along the periphery. The Germans did this skillfully in the two world wars as did the Confederate armies in the American Civil War. Napoleon seems to have welcomed multi-front wars as he enjoyed fighting coalitions, and was skillful at pitting them against each other, but a coalition finally did him in.

Fighting successfully from interior lines does not imply strictly defensive tactics. It often requires the tactical offense to keep the enemy off balance and disrupt a unified effort on the part of the adversary from multiple fronts at once. For example, in 1862, Lee used the Union fixation with an attack on the Confederate capitol at Richmond through the Virginia Peninsula country as the matador’s cape to enable an attack on a smaller Union army at west of Washington at the Second Battle of Bull Run. This cleared the way for Lee to invade Maryland forcing the bulk of the Union Army to follow him, thus relieving the threat to Richmond. Israel always fought on interior lines in its early wars. It usually attempted to land the first killing blow against the Egyptians which it considered to be the most dangerous enemy. It generally then turned on the next most dangerous foe (almost always the Syrians).

The problem with fighting on interior lines is that time is on the other side. Nations that that opt to fight multiple foes at once generally lose, even if they fight brilliantly at the tactical level and have military genius on their side. Germany lost both World Wars, and Napoleon was finally done in by enemies attacking on many fronts at once. Nations that fight on interior lines have a losing record in the long run; the cases Frederick the Great and Israel in its early wars are exceptions. In general, wars fought along interior lines last a long time with the defender hoping that one of his adversaries will crumble first; again, the 1967 and 1973 Arab-Israeli wars are exceptions to the rule. Even with a military genius such a Lee or Napoleon in command, the side fighting a multi-front war on interior lines has the odds stacked against it, but defeating an enemy fighting on interior lines usually requires time. World War one lasted four years, the second six, and it took nearly two decades to bring Napoleon down. Iraq probably doesn’t have time if it wishes to survive as a viable nation-state.

Fighting a multi-front war is usually the result of a failure of grand strategy. This was the greatest fear of Bismarck, Germany’s Iron Chancellor. When Bismarck was dismissed by Kaiser Wilhelm II, who was not a notable strategist, the seeds were sewn for the catastrophe of World War I. Hitler’s attack on Russia before he had dealt with Britain proved equally disastrous for Germany in World War II; however, this is not World War II. The Islamic State needs enemies to justify being constantly on a war footing; its leaders need constant struggle (jihad) to keep its restive warriors busy. Like the coalitions that Napoleon faced, the Islamic State is dealing with a collection of enemies that hate each other as much as they hate the jihadists. This allows ISIS to shift forces from front to front to keep its enemies off balance. For example, it would not be surprising to see ISIS re-attack Tikrit once Iraqi forces have shifted to react to the al-Anbar threat.

The relative sophistication of the Tikrit-Ramadi campaign shows both the military strength and weakness of the Islamic State. Its primary strength is in a very good and dedicated cadre of light infantry. The weakness is that it is not a hit and run guerilla force. The jihadists have taken terrain and now have to defend it. In military jargon, their light infantry is their “center of gravity”, their source of strength. Once it is destroyed, the Islamic State becomes ISIS, just another terrorist group on the run.

If the Iraq and its leader Prime Minister Haider al Abadi are to survive, the army of the Islamic state must be defeated and destroyed at Mosul and it must be done before the year ends. He will need at least 10,000 American ground troops temporarily deployed to Iraq to re-take Mosul in a timely manner.

There are two good strategic reasons for American ground forces to get involved in this situation. The first is that a quick destruction of the Islamic State would prevent it from becoming a sanctuary for future terrorist attacks on the American homeland such as Afghanistan became in the last decade. Second, it would eliminate Iran as a primary player in Iraqi security and do much to decrease the fears of our regional allies that we are ceding the middle-east to the Iranians. Once the Islamic State is defeated, the maintenance of a rotating brigade of combat ready troops capable of retraining the Iraqi Army would go a long way toward cementing our continued role as a regional player.

Betting on Haider’s ability to make good on his promise to reconcile Iraq’s ethnic and sectarian differences is a calculated risk, but it is one worth taking. Having spent billions in dollars and thousands in lives to build a working Iraq, we should give it one last try.

Gary Anderson is a retired Marine Corps Colonel. He was the senior U.S. Military Liaison Advisor to the UN mission in Mogadishu, Somalia in 1993 and was the Chief of Staff for the Marine Corps Warfighting Lab when it conducted the URBAN WARRIOR experiments from 1998-90.

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