Given the significant (but decreasing) U.s. com- mitment in iraq and the considerable (and in- creasing) U.s. commitment in afghanistan, as- sembling an invasion force for iran would be a daunting task. however, it would pale compared to the needs of the postconflict security and re- construction mission.
This will likely prove true even if Washington has learned the lessons of iraq and mounts the inva- sion and occupation of iran exactly as it should have done in iraq. all low-intensity conflict op- erations, whether a counterinsurgency campaign or a stability operation like securing postinvasion iran, require relatively large numbers of security forces because the sine qua non of success is se- curing the civilian populace against widespread violence. scholars and counterinsurgency ex- perts have suggested that it takes about 20 secu- rity personnel per 1,000 people to secure civilians against insurgencies and other forms of violence bilities, but if the U.s. Navy and air Force bring
their full might to bear, they could methodically crush iran’s air and sea defenses in a matter of weeks, with relatively few losses. however, this will require a major commitment of american minesweeping, surface warfare, and (especially) air assets.
Beyond this, the navy would likely have to con- tribute much greater air support to the ground campaign than was the case for the invasions of either iraq or afghanistan. certainly, some U.s. aircraft (like B-2 stealth bombers) could fly from the continental United states (and Washington might get British permission to use the island of Diego Garcia for B-1s, B-52s, and tankers), but unless the Gcc states, iraq, and/or central asian countries could be persuaded to allow the U.s. air Force to operate from nearby airfields, the vast majority of american aircraft would have to operate from carriers in the Persian Gulf and North arabian sea. Given the extent to which modern U.s. ground operations rely on air sup- port (including during occupation and counter- insurgency campaigns), this suggests that three or more carriers would need to be committed to this campaign, at least until iranian air bases could be secured and developed to handle U.s. air Force planes.
similarly, if the United states were denied access to its many bases in the Persian Gulf region, as seems likely, the navy would have to bring in ev- erything needed to support the invasion, and U.s. engineers would have to build facilities at iranian ports to make them capable of supporting a mas- sive force.
indeed, because it is likely that the United states would have little regional support, because the distances involved would be much greater than in iraq (distances from major iranian ports to tehran are anywhere from one and a half to three times as great as the distance from the Kuwaiti
states. During that time, the United states would doubtless have to maintain 100,000 to 200,000 troops in iran, even under ideal circumstances of full iranian cooperation and minimal resistance (or even criminality). if one assumes that dur- ing the same period, total U.s. military commit- ments in iraq and afghanistan will also remain in the 100,000 to 150,000 troop range (with the assumption of a declining commitment to iraq and a growing commitment to afghanistan, albeit smaller than the one in iraq at its peak), it is hard to imagine how the current level of american ground forces could sustain such deployments over the period of years that would be required. only a major, rapid increase in the size of the armed forces would make that possible without destroying the National Guard and military re- serve systems—an increase that perhaps would necessitate some form of partial conscription. Moreover, it obviously would be unwise to as- sume the best case. The Bush administration’s insistence that only the best case was possible in iraq lies at the root of the concatenation of mis- takes that produced the worst case in iraq from 2003 to 2006. iranians are fiercely nationalistic, and while many would welcome the end of their current regime and the establishment of a better relationship with the United states, the evidence suggests that most would fiercely oppose a U.s. invasion. accounting for more realistic scenarios increases the challenges and requirements for common in postconflict reconstruction.33 This
ratio suggests that an occupation force of 1.4 mil- lion troops would be needed for iran.
There is reason to believe that high-quality troops with lavish support assets (like the U.s. military) can get away with less than the canonical figure. however, even if the United states, by relying on far superior training, technology, and tactics, could cut that number in half, the remainder still represents essentially the entire active duty com- ponent of the U.s. army and Marine corps. even if it were only necessary to maintain such a large force in iran for the first six months, after which the United states could begin drawing down its forces quickly (as experience in the Balkans and even iraq suggests is possible), such a commit- ment would certainly require a massive mobili- zation of the National Guard and both the army and Marine reserves. it might necessitate their total mobilization for at least six to twelve months and might also require major redeployments away from iraq and afghanistan.
again, assuming a best-case scenario in which the proper application of the lessons learned from iraq and afghanistan enables the invasion and occupation of iran to go more easily and be more peaceful and successful, it would take several years to establish a stable, legitimate government with competent, loyal security forces that can take over the security of their country from the United
33 Bruce hoffman, “insurgency and counterinsurgency in iraq,” raND corp., June 2004; Kalev i. sepp, “Best Practices in counterinsurgency,”
Military Review 85, no. 3 (May–June 2005): 9; James t. Quinlivan, “The Burden of Victory: The Painful arithmetic of stability operations,” RAND Review, summer 2003, available at <http://www.rand.org/publications/randreview/issues/summer2003/burden.html>. also, James t.
Quinlivan, “Force requirements in stability operations,” Parameters (Winter 1995): 56–69. Quinlivan has demonstrated that stabilizing a country requires roughly twenty security personnel (troops and police) per thousand inhabitants, just as counterinsurgency operations do. in his words, the objective “is not to destroy an enemy but to provide security for residents so that they have enough confidence to manage their daily affairs and to support a government authority of their own.” even in iraq, this “canonical” figure has proven valid. iraq’s population outside of the Kurdish zone—which was adequately secured by the Kurdish peshmerga (fighters) and thus never experienced the same levels of violence as the rest of the country—was roughly 23 million people. This would suggest the need for 460,000 committed security personnel. although U.s. troops working with small numbers of competent and reliable iraqi security forces were able to secure large swathes of the population within six to twelve months of the start of the surge, the change in U.s. strategy and tactics, the end of the Battle of Baghdad, and the onset of the anbar awakening (all of which occurred in late 2006 and early 2007), they were not able to secure the entire country, and most of southern iraq—with nearly 40 percent of iraq’s population—lay beyond their control. only when the total of U.s. and competent iraqi troops exceeded 450,000-500,000 in early 2008 were these forces able to expand their control to the south without jeopardizing the gains made in the center and west.
would likely be as mismanaged and tragic as it was in iraq from 2003 to 2006.
Pros and Cons
The following are the advantages and disadvantag- es of the Invasion approach.
advantages:
The most important and obvious advantage of mounting an invasion of iran is that it would “solve” all of Washington’s current problems with tehran. iran’s nuclear pro- gram would be obliterated. The regime that supported so many terrorist, insurgent, and revolutionary groups that sought to harm the United states and/or its regional allies would be gone. hizballah, hamas, the Pal- estinian islamic Jihad, and the like would have lost one of their most important back- ers. and Washington would no longer have to worry about how to deal with a regime it considers both threatening and madden- ingly opaque.
Moreover, a policy focused entirely on mounting an invasion of iran would be implemented entirely under american control. Washington might find itself in a position where it would not need to wor- ry about convincing reluctant allies, since there would be no expectation that they could be convinced nor any expectation that they would help. Furthermore, Wash- ington would not need to persuade the ira- nian leadership (or even iranian dissidents) to cooperate with the United states—it could force them to do so, or simply get rid of them and bring in a whole new group. Finally, it would mean employing the most
powerful, most skillful, and most deci- sive tool in the U.s. strategic toolkit—the the occupation of iran even more, to levels that
realistically only could be met by a major, rapid expansion of the U.s. armed forces, for which the american people appear to have little interest.