(Analyst's note:  I for one, absolutely support reasoned approaches.  With this Islamist jihadist enemy to do nothing or to continue down the path of political correctness is in reality taking the path of national suicide.)

After the Ft. Hood tragedy, I have been asked by many to address what the US must do with American Muslims in the military. Some took an emotional response and promoted the view that Muslims should not be allowed in the US military. Others tried to approach the issue in a more rational manner. The WSJ addressed some aspects of this sensitive topic (See: Muslim Population in the Military Raises Difficult Issues by Yochi J. Dreazen Saturday Sunday 7-8 2009 US printed edition). The possibility of a backlash against Muslims in the military was also discussed on the CNN.I will summarize my answer as follows.
 
There are three possibilities (or options) for the reaction:
Option 1: Stop all Muslims from working in the military
Option 2: Give permission to Muslims in the US Army so that they do not fight against their fellow Muslims.
Option 3: Do nothing  
 
The first option (to stop all Muslims from working in the military) will deprive the US from benefiting from the experience of true moderate Muslims who also fight Islamic Radicalism. The experience of these moderates can be pivotal and invaluable in achieving the needed victory over radical Muslims. This situation makes it imperative for the US officials to set parameters to define who is moderate and who is radical. Using proper parameters to define these terms can allow the US to use the knowledge of true moderate Muslims effectively to fight radical Islam and at the same time avoid discrimination against all Muslims. Failure to set these parameters can allow many radicals to infiltrate sensitive positions in the military and may end in catastrophic consequences.   
 
The second option (to give exemptions to Muslims in the US military so that they do not fight against their fellow Muslims) raises several important concerns as well.
 
1-     This option could be seen as a form of discrimination against non-Muslims in the military. In other words, why should non-Muslims take the risk of going to war and die while their fellow Muslim soldiers are refusing to defend their nation? In this case we will face one of the most bizarre situations in history when non-Muslims have to die to defend Muslims who sympathize with the enemy and refuse to fight it.
 
2-     What if ALL US military soldiers converted to Islam? Shall we just surrender to Islamic Radicals because No one in the military is willing to defend the country anymore?
 
3-     Accepting this option casts doubt on the loyalty of these Muslims (who refuse to fight another Muslim to protect the US) to the US.  If these Muslims were more loyal to their "Umma" (Muslim nation) than to the US then they should be considered a fifth column and MUST not be allowed to work in military or any sensitive position.
 
4-     Those American Muslims who refuse to fight another Muslim to defend the US must be ready to answer the following imperative question: Is it OK for them to kill Christians or Hindus if they attacked the US but it is unacceptable by them to kill Muslims if they did attacked their country?
 
5- If Radical Muslims declared war on the US, will Muslims in US military allow the killing of their fellow American citizens to avoid fighting their radical Muslim brothers? In other words, are the lives of their fellow Americans less in their view than the lives of the radical Muslims?
 
As we can see the second option raises serious concerns.
 
If the third situation (Do Nothing) is accepted as the best type of reaction, many Islamic radicals will be able to infiltrate our military. In this situation, the disaster of Ft. Hood may look trivial compared to what could happen if these radicals managed to use radiological, biological, or chemical weapons against our society. In such a case, we may wake up one day to the news that an Islamic radical in US army released a lethal bacteriological or viral agent inside the US that will kill thousands of people or more and will destroy the economy of the country. The tragedy that could happen in this case is far beyond words to describe it. Doing nothing and just waiting for another attack by a radical Islamist inside the US is a catastrophic approach. We were just lucky in the US that Dr. Nidal Hasan, who allegedly committed the atrocity in Ft. Hood, did not have access to a biological weapon. An important approach to deal with such a complex situation is to educate senior officials in the US how to detect early signs of radicalization-both overt and covert- as this can allow these officials to take appropriate measures to prevent a possible disaster.