The Khalifah does not have a fixed term of office; as long as the Khalifah preserves the Shari’ah and he implements its rules, and is capable of carrying out the affairs of the State, he remains as a Khalifah as long as his situation does not change to one that would remove him from the leadership of the State. If his state changes in this manner, then it is obligatory to remove him from his position at that time.

The proof for this is that the text of the pledge of allegiance mentioned in the narrations came in an absolute form and was not restricted by any specific period. Additionally, the righteously guided Khulafaa’ were each contracted upon a pledge in an absolute form, which was the pledge mentioned in the narrations, and their terms were not fixed. So each one of them undertook the Khilafah from the time they were contracted until they died, which is an Ijma’ of the companions that the Khilafah does not have a fixed term, rather it is absolute, and if someone is contracted, they remain as Khalifah until they die. This is the case unless something occurs to the Khalifah which would remove him, or make it necessary to remove him at that time. But this is not a limit upon the term of the Khilafah, rather it would be something that occurred which led to a deficiency in the conditions of the Khilafah, since the form of the pledge of allegiance which has been determined by the Shari’ah texts and the Ijma’ of the companions made the Khilafah an indeterminate term. However, it is limited by the undertaking of what he was contracted upon, which was the Book and the Sunnah, in other words, the implementation of the Shari’ah; if he did not protect the Shari’ah or did not implement it, then he would display open disbelief which would make resistance against him obligatory upon the Ummah due to the narration.

. » إِلاَّ أَنْ تَ رَوْا كُفْرًا بَ وَاحًا « .

“Unless you witness open Kufr” (agreed upon narration from ’Ubadah b. Al-Samit).