Obama's three options would not necessarily solve the chemical weapons problem but could demonstrate that the United States is taking some form of action in response to the growing Syrian crisis, albeit with significant associated risk.
The first and most direct form of limited intervention is the establishment of a no-fly zone. This would require the U.S. military to conduct a serious suppression of enemy air defenses (SEAD, in military parlance) campaign before it could even start combat air patrols to enforce the grounding or destruction of the loyalist forces' air power. The no-fly zone would eliminate the loyalist forces' most significant advantage over the rebels and accelerate the downfall of the regime. However, this could complicate the transfer of power, which would be affected by a lack of unity among the rebels. It could also lead extremist elements of each major sect to retreat to territorial enclaves and would likely lead civil war to engulf the northern Levant.
Moreover, this plan would not address the problems with the chemical weapons. It would still endanger U.S. military personnel (they could be killed in action or become prisoners of war), and would be a costly endeavor with serious potential for mission creep — as was seen in Libya, where a no-fly zone became a no-armor-on-the-ground zone. To facilitate this scenario, the United States would likely need to position at least one fleet aircraft carrier in the U.S. 6th Fleet area of responsibility in order to support the need for constant aircraft in the air space.
Obama's second option is some form of targeted strike campaign utilizing aircraft and cruise missiles. Such a campaign would be reminiscent of Operation Desert Fox (the bombing of Iraq in 1998) and would be designed to send a clear message to Syria without exposing U.S. forces to a sustained operation like a no-fly zone would. The potential target sets are diverse. If the administration wanted to address the chemical weapons issue, it could directly strike facilities, but this could easily cause contamination near populated areas and would not necessarily destroy an entire stockpile within a facility. Furthermore, the effectiveness of these strikes depends largely on accurate intelligence. The United States appears to have a measure of fidelity on some locations and on the movement of various stockpiles, but there are too many options for mobile platforms and smaller storage sites for planners to have full confidence that all scenarios have been accounted for.
Another strategy would be to target the chemical weapons in an oblique manner by focusing on potential delivery systems, such as Scuds and artillery batteries, but this, too, could not be done comprehensively. It is not possible to destroy every Scud missile, artillery piece, rocket system and mortar capable of delivering a chemical weapon. U.S. planners could also target airfields and aircraft concentrations. Targeted strikes would demonstrate that the United States is taking action, and they would represent Washington's most scalable option. Additionally, this option would not place weapons in a position where they could later be turned back on the United States, and it would not put U.S. service personnel in danger as much as a wider no-fly zone operation would.
Depending on the scale of this operation, considerably fewer conspicuous military platforms would have to be brought directly into the region compared to a no-fly zone. For instance, guided missile submarines could be parked quietly off the coast and combined with aircraft out of European bases. The main constraints of this option are that the plan still requires direct involvement and has the potential for mission creep, while any action that influences the direction of this fight could have disastrous consequences.
The third option, and according to recent reports the one receiving the most consideration from the Obama administration, is direct lethal aid to the rebels. The U.S. military could easily manage this — the United States handles logistics well and has solid weapon systems, such as anti-tank guided missiles and surface-to-air missiles, that can benefit the rebels greatly.
This plan represents the low end of assumed risk on limited intervention possibilities. The United States is already indirectly involved in vetting and arming specific groups in Syria. Putting the plan in motion would entail a massive ramping up of that process. The plan, however, also begs the question of whether rebels can really be vetted, armed and shaped in a way that will achieve a desirable outcome in Syria after the regime collapses. Additionally, the rebels who are empowered would have to be trusted and trained to assume control of fairly advanced weapon systems, including the chemical weapons that they would inherit. Once these weapons are in rebel hands, it would be extremely difficult to get them back. This is reminiscent of similar armament programs in Afghanistan in the 1980s that had repercussive effects for decades. The potential for political or military backlash is large.
The Syrian civil war is complicated and offers no easy solution to the United States. Currently, the situation is being managed as indirectly as possible, but this strategy might become untenable for Obama. As the war progresses, there are real reasons for U.S. restraint, but the aforementioned actions cover the basic spectrum that Obama is examining as pressure on the United States increases.
