Is it permissible to rebel against the ruler?
Question

                There are people who think that because some of the rulers commit acts of kufr and sin, we are obliged to rebel against them and attempt to change things even if that results in harming the Muslims in that country, at a time when there are many problems in the Muslim world. What is your opinion?
Praise be to Allah.The basic comprehensive principle of sharee’ah is that 
          it is not permitted to remove an evil by means of a greater evil; evil 
          must be warded off by that which will remove it or reduce it. Warding 
          off evil by means of a greater evil is not permitted according to the 
          scholarly consensus (ijmaa’) of the Muslims. If this group which wants 
          to get rid of this ruler who is openly committing kufr is able to do 
          so, and can bring in a good and righteous leader without that leading 
          to greater trouble for the Muslims or a greater evil than the evil of 
          this ruler, then that is OK. But if rebellion would result in greater 
          trouble and lead to chaos, oppression and the assassination of people 
          who do not deserve to be assassinated, and other forms of major evil, 
          then that is not permitted. Rather it is essential to be patient and 
          to hear and obey in matters of good, and to offer sincere advice to 
          the authorities, and to pray that they may be guided to good, and to 
          strive to reduce evil and increase good. This is the correct way which 
          should be followed, because that is in the general interests of the 
          Muslims, and because it will reduce evil and increase good, and because 
          this will keep the peace and protect the Muslims from a greater evil.