It is not required for Muslims to always have a caliph from the Quraish tribe, nor even from the Arabs. Islam is not a tribal or racist religion; it is a religion for all people and for all times.
Dr. Muzammil Siddiqi, former president of the Islamic Society of North America, states the following: “There is a well-known Hadith in which the Prophet (peace and blessings be upon him) states that “The imams are from the tribe of Quraish” (Reported by Ahmad). However, it is not necessary to have the caliph or the imam from the tribe of Quraish or from Arabs, for Islam is neither a tribal nor a racist religion, as it addresses all peoples in all times.
The Prophet (peace and blessings be upon him) did mention that after him there will be khulafa’ or caliphs to rule Muslims. The caliph is the representative of the people and he should be chosen by them. He should be a pious Muslim and should be capable of discharging his duties as the head of the Muslim State.
There is a Prophetic Hadith that states that that the imams are from the tribe of Quraish. But this is not obligatory according to most of the Muslim jurists. It was a recommendation by the Prophet (peace and blessings be upon him) for his time because the Quraish were greatly respected and they could bring various tribes together. There are also other Hadiths of the Prophet (peace and blessings be upon him) that state that Muslims should listen and obey their rulers, even if they are from Habashah or Abyssinia, which means ‘from a distant land, of different color and race.’
It is not required for Muslims to have a caliph always from the tribe of Quraish, or even from the Arabs. Islam is not a tribal or racist religion; it is a religion for all people and for all times.”