What can a student do to respond to faculty/administration decisions based on current political events? We are from Kuwait. Our university often has many foreign professors visiting for extended periods. 

In my particular department, the head has now begun rejecting professors from the US, and starting to send those back who are here already, the reason being that this is in response to the immigration ban imposed on Muslims from certain countries (however not Kuwait) by the US. 

How should one deal with this as a student in this department? My first reaction was that this is obviously wrong and unfair, but I know from my advisor that the department head also feels that it is unfair to the rest of the world's professors that Americans can ban others from entering their country, but in turn can themselves go almost anywhere they want. So it is according to him a fair policy.
As a student, unfortunately there is probably nothing you can do about the situation -- except to remind yourself that one day you might be in a position of power and influence yourself, and able to do things differently.

Things might be different if there were was a particular American professor you wanted to invite to campus for academic reasons. In that case I would express to your chair that you understand his concerns, but talk about what you hoped to gain academically from such a visit.

The immigration ban is strongly opposed by many American academics. If there iss someone particular you would like to invite, you might ask if he/she has done anything to fight the ban (e.g. calling one's senators, participating in protests, donating to the ACLU). In such a situation, your chair might be willing to reconsider. 

That said, I would not recommend pushing the issue hard if at all. You are still a student, and as such you don't have a lot of political clout.