The kufr of those who rule by man-made laws
Question

                Is the one who fails to rule by that which Allaah has revealed and bases the entire legal system on man-made laws a kaafir? Should we differentiate between him and one who judges according to sharee’ah, but may rule in a manner contrary to sharee’ah on some issues, because of his own whims and desires or because of a bribe, etc.?
Praise be to Allah.Yes, 
          we must make this distinction. The one who rejects the law of Allaah 
          and casts it aside, and replaces it with man-made laws and the opinions 
          of individuals has committed an act of kufr which puts him beyond the 
          pale of Islam. Whereas the one who adheres to the religion of Islam, 
          but is a sinner and wrongdoer by virtue of his following his whims and 
          desires in some cases, or pursuing some worldly interest, but admits 
          that he is a wrongdoer by doing so, is not guilty of kufr which would 
          put him beyond the pale of Islam. 
 Whoever 
          thinks that ruling by man-made laws is equal to ruling by sharee’ah, 
          and thinks that it is OK to do that, is also guilty of kufr that puts 
          him beyond the pale of Islam, even if it is only in one instance.