Those who declare the Muslim rulers to be disbelievers are from the Khawarij
Question:
What is our position towards those who make takfeer of the Muslim rulers today, generally and in detail? Are they (those who make takfir of the rulers) considered to be from the Khawarij?
Answer:
Those who declare the Muslim rulers to be disbelievers in general, then these are from the most extreme of the Khawaarij because they do not exclude anyone and give the ruling of disbelief to all the Muslims rulers. So this is most severe form of the madhab of the Khawaarij, because they generalised (the declaration of disbelief).
Muftis