Sheikh Yusuf Al-Qaradawi, in which he states the following: “Obtaining the nationality of a non-Muslim country is sometimes regarded as a perfidious act in Islam (act of betrayal of Allah, His Messenger, as well as Muslims), if there is a state of war between Muslims and such a country. For this reason, Tunisian scholars, during the French occupation, gave a Fatwa stating that anyone who obtained French nationality, during that period of time, would be regarded as a renegade and apostate (forsaking Islam), because this was a means of resisting occupation and a excellent weapon of Jihad.
However, in peaceful times, obtaining nationality from non-Muslim countries may provide protection and power for some Muslims who need to travel to these countries. By virtue of nationality, authorities of such countries have no right to expel Muslims. Moreover, Muslims then have the right to vote, and this gives them power of influence, as the candidates try to appeal to them to win their votes.
Thus, obtaining nationality is not, per se, good or bad in and of itself, rather it is considered to be this or that according to the benefit it may realize or the harm it may inflict upon Muslims. For example, Palestinians obtaining Israeli nationality is an implicit recognition of the state of Israel; however to get nationality from some Western country, with a goal to enhance the position of Muslims there, is not forbidden at all.”