Below is my translation of an Arabic-language paper published by the Assembly of Muslim Jurists of America (AMJA) in 2007, and presented at their 2008 careers conference in Houston, which provides guidelines for American Muslims on what they can and cannot do vis-à-vis infidel legal systems. The paper makes clear that according to Islam, the only legitimate law is that which comes from Allah, and in fact authority to make laws rests with Allah alone. This renders every other legal system—including the American system—illegitimate.
Since the fact nevertheless remains that many Muslims do live under such 'infidel' legal systems, the paper provides guidelines for how they should act under these systems, specifically addressing issues such as Muslims studying man-made law (i.e. non-Islamic law), Muslims governing under infidel legal systems, Muslims working as judges or lawyers or prosecuting cases in infidel courts, and Muslims granting powers of attorney to non-Muslims in disputes. Throughout the paper it is made abundantly clear that Muslims should view the American and other non-Muslim legal systems as infidel systems, and that they are only to participate in them in specific circumstances in order to benefit Islam and Muslims generally. They are specifically instructed to feel hatred in their hearts toward such infidel legal systems, and to do everything within their power to make the Islamic Shari'a supreme, even if that means engaging in deception in certain cases.