These days alot of groups have emerged and one of these groups are called takfiris/Khawarij. They have innovated in the religion in many areas specially when it comes to the Rulers. The make takfir(making someone a Kaffir) a blank check. They also make it permissible to criticize the rulers. All these goes against the Sunnah and the way of the salaf. It also resembles the way of the Khawarij. the khawarij use to make the muslim blood Halal and they use to criticize the rulers and go against them.
Here is a good article concerning how to advise the Rulers. It is written by sheikh Ibn Baaz. Sheikh Ibn Baaz is one of the great scholars of our Era. Allah has blessed him with Knowledge and righteouness. He also gave a fatwa against Bin laden and his group, AL-Qaida.
http://www.spubs.com/sps/