The Islamic Personality by Sheikh Taqīuddīn An-Nabahānī

It is not allowed to have more than one Khalifah in the world because ‘Abdullah bin ‘Amru bin al-‘Aas (ra) narrated that he heard the Messenger of Allah (saw) say:

Also Abu Saeed al-Khudri narrated that the Messenger of Allah (saw) said:

And ‘Arfaja said that he heard the Messenger of Allah (saw) say:

Abu Hazim also narrated that he accompanied Abu Hurairah (ra) for five years and heard him narrate about the Messenger of Allah (saw) saying:

If the Khilafah was established for two Khalifahs in two countries at the same time, it would not be valid for either of them because the Muslims are not allowed to have two Khalifahs. It is not correct to say that the bay’ah is valid to the one that had it first because the matter is to establish a Khalifah, not to make a race for it. Also it is the right of all Muslims, not the right for the Khalifah, so the matter must go back again to the Muslims to establish one Khalifah in case when they had established two Khalifahs. It is incorrect to suggest a ballot between them because the Khilafah is a contract, and the ballot is not included in the contract. And it is incorrect to refer to the saying of the Prophet (saw):

Because this is the case if a pledge is given to Khulafaa when there exists a Khalifah; so the pledge is not valid except for the first one whose pledge was contracted, and whoever comes afterwards could not have the pledge contracted to him. The case under discussion is that if the Khilafah is established for two Khalifahs when the majority of the influential people elected two Khalifahs at the same time, and the pledge of each of them was contracted legally. So the two contracts are cancelled and the matter must be returned to the Muslims; if they established the pledge for one of them then it is contracted anew, not as a confirmation to his previous case. And if they established it to other than them, then it is contracted (to that other person). Thus the matter is a right to all Muslims not to persons who enter in a race for it. And if two Khulafaa were established, and the majority of the influential people in the affairs of ruling and Khilafah sided with one of them and it was they who elected him, while the minority was with the other, then the pledge would be for the one who the majority of the influential people in the matters of ruling elected. (This is so) whether he was elected first, second or third, because he is considered the legal Khalifah when the majority of the influential people elected him. The others must make a pledge to him for the sake of unity of the Khilafah; otherwise the Muslims will fight him because the Khilafah is contracted by the pledge of the majority of the Muslims. He thus becomes a Khalifah who must be obeyed by all Muslims and it becomes haram to elect another person.

However, the reality of the ruling is that the majority of the influential people, in whose hands lays the affairs of ruling, are usually found in the capital because that is where the main affairs of ruling are conducted. So if the residents of a province or provinces elected another Khalifah and the pledge to the one who is in the capital was given first, then the Khilafah is for him because the pledge given by the people of the capital is a connotation which indicates that the majority of the influential people are on his side, and the pledge in this case is for the first. But in the case that the Khalifah in the provinces was elected first, the preference is given to the one who has the majority of influential people on his side because the precedence of the people of the provinces in giving the pledge weakens the connotation that the majority of the influential people are present in the capital. In any case, it is not allowed to retain more than one Khalifah, even if this leads to fighting against the one who did not have the Khilafah contracted to him.