Is it permissible for him to study American law and to teach it or practise it?
Question

I live in the USA, where there are a lot of troubles everywhere, and the Muslims are suffering from problems and difficulties in life everywhere. My question is: is it permissible for me to study American law and get a diploma in it, and practice it in the USA? There are different kinds of laws here in the USA; for example, there is immigration law, criminal law, national security, labor laws and so on. I think criminal law is the most appropriate for me. I have a number of choices: either I can practice law here, or I can become a teacher and teach American history to students, or I can leave and teach students in a Muslim country, which is what I prefer. What is your opinion?
Praise be to Allah.Firstly:
Undoubtedly living in a Muslim country, among fellow Muslims, is better and preferable, and is further removed from trials and doubts than living in a non-Muslim country. Migration from non-Muslim countries to Muslim countries is obligatory upon the Muslim who is living in a non-Muslim country, if it is possible for him to do so, when he is not able to practice his religion openly and establish its rituals and duties, or he fears for himself lest he be tempted by desires and confused by doubts, especially in that land where the Muslims are suffering all kinds of trials and tribulations.
See the answer to question no. 13363
Based on what is mentioned in your question, what we prefer for you is what you are inclined to yourself:
Which is to look for suitable work and permanent residency in some Muslim country, even if the salary there is lower and worldly comforts there are less available. This is undoubtedly safer in terms of your religious commitment and will make you feel more at ease.
If that is not possible, or it is too difficult to achieve that, then until it is possible for you to do that, we advise you to work in the field of teaching history, because this is further removed from the shar‘i infractions that would be involved in studying or practising man-made American law, which is inherently contrary to the laws of Allah, may He be exalted.
And whenever the first solution becomes possible for you, then seize the opportunity and strive to do that which is safer for your religious commitment and more beneficial for you.
See also the answers to questions no.  99983, 11233 and 111923
And Allah knows best.