Khilafah

 The term caliphate, refers to the first system of government established in Islam and represented political unity of the Muslim Ummah. In theory, it is a constitutional republic,which means that the Head of the state, the Caliph, and other officials are representatives of the people and of Islam and must govern according to constitutional and Religios Law. In its early days, it resembled elements of direct democracy.

It was initially led by Prophet Muhammed(PBUH)'s disciples as a continuation of the leaders and religious system the prophet established, known as the 'Rashidun caliphates'. A "caliphate" is also a state which implements such a governmental system.The caliphate was "the core leader concept of Sunni Islam, by the consensus of the Muslim majority in the early centuries.

The following excerpt from the Holy Qur'an, known as the 'Istikhlaf Verse', is used by some to argue for a Quranic basis for Caliphate:

God has promised those of you who have attained to faith and do righteous deeds that, of a certainty, He will make them Khulifa on earth, even as He caused [some of] those who lived before them to become Khulifa; and that, of a certainty, He will firmly establish for them the religion which He has been pleased to bestow on them; and that, of a certainty, He will cause their erstwhile state of fear to be replaced by a sense of security [seeing that] they worship Me [alone], not ascribing divine powers to aught beside Me. But all who, after [having understood] this, choose to deny the truth – it is they, they who are truly iniquitous!" [24:55] (Surah Al-Nur, Verse 55)

In the above verse the word Khulifa (the plural of Khalifa) has been variously translated as "successors" and "ones who accede to power".

Small subsections of Sunni Islamism argue that to govern a state by Islamic law is, by definition, to rule via the Caliphate, and use the following verses to sustain their claim.

So govern between the people by that which God has revealed (Islam), and follow not their vain desires, beware of them in case they seduce you from just some part of that which God has revealed to you

(Holy Qur'an 4:49)

O you who believe! Obey God, and obey the messenger and then those among you who are in authority; and if you have a dispute concerning any matter, refer it to God and the messenger's rulings, if you are (in truth) believers in God and the Last Day. That is better and more seemly in the end.

(Holy Qur'an 4:59)

The caliph was often known as Amir al-Mu'minin (أمير المؤمنين) "Commander of the Believers". Muhammad established his capital in Medina, and after he died it remained the capital for the Rashidun period. At times in Muslim History there have been rival claimant caliphs in different parts of the Islamic world, and divisions between the Shi'a and Sunni communities.

According to Sunni Muslims, the first caliph to be called Amir al-Mu'minin was Abu Bakr Sidhik, followed by Umar Bin Al-Khatab, the second of the Four Rightly Guided Khalifs. Uthman Ibn Affan and Ali Ibn Abi Thalib also were called by the same title, while the Shi'a consider Ali to have been the only truly legitimate caliph^.

The rulers preceding these first four did not receive this title by consensus, and as it was turned into a monarchy thereafter.

After the first four caliphs, the Caliphate was claimed by dynasties such as the Umayyads, the Abbasids, and the Ottomans, and for relatively short periods by other, competing dynasties in Al-Andalus, North Africa, and Egypt. After the collapse of the Ottoman Empire, Mustafa Kamal Atta Turk officially abolished the system of Caliphate in Islam (the Ottoman Empire) and founded the Republic of Turkey, in 1923. The Kings of Morocco still label themselves with the title Amir al-Mu'minin for the Moroccans, but lay no claim to the Caliphate.Some Muslim countries, like Somalia, Indonesia and Malasyia  were never subject to the authority of a Caliphate, with the exception of Aceh, which briefly acknowledged Ottoman suzerainty.Consequently these countries had their own, local, sultans or rulers who did not fully accept the authority of the Caliph.

Hadith

The following Hadith from Musnad Ahamed Ibn Hanbal can be understood to prophesy two eras of Caliphate (both on the lines/precepts of prophethood).

Hadhrat Huzaifa narrated that the Messenger of Allah said: Prophethood will remain among you as long as Allah wills. Then Caliphate (Khilafah) on the lines of Prophethood shall commence, and remain as long as Allah wills. Then corrupt/erosive monarchy would take place, and it will remain as long as Allah wills. After that, despotic kingship would emerge, and it will remain as long as Allah wills. Then, the Caliphate (Khilafah) shall come once again based on the precept of Prophethood.

In the above Hadith the first era of Caliphate is commonly accepted by the Muslims as that of the Rashidhun Caliphate.

Nafi'a reported saying:

It has been reported on the authority of Nafi, that 'Abdullah b. Umar paid a visit to Abdullah b. Muti' in the days (when atrocities were perpetrated on the People Of Medina) at Harra in the time of Yazid b. Mu'awiya. Ibn Muti' said: Place a pillow for Abu 'Abd al-Rahman (family name of 'Abdullah b. 'Umar). But the latter said: I have not come to sit with you. I have come to you to tell you a tradition I heard from the Messenger of Allah. I heard him say: One who withdraws his band from obedience (to the Amir) will find no argument (in his defence) when he stands before Allah on the Day of Judgment, and one who dies without having bound himself by an oath of allegiance (to an Amir) will die the death of one belonging to the days of Jahiliyyah. – Sahih Muslim, Book 020,

Hishan Ibn Urwah reported on the authority of Abu Saleh on the authority of Abu Hurairah that Prophet Muhammad(PBUH) said:

Leaders will take charge of you after me, where the pious (one) will lead you with his piety and the impious (one) with his impiety, so only listen to them and obey them in everything which conforms with the truth (Islam). If they act rightly it is for your credit, and if they acted wrongly it is counted for you and against them.

Muslim narrated on the authority of Al-A'araj, on the authority of Abu Hurairah, that Prophet Muhammad(PBUH) said:

Behold, the Imam (Caliph) is but a shield from behind whom the people fight and by whom they defend themselves.

Muslim reported on the authority of Abdel Aziz AL-Muqrin, who said,

I accompanied Abu Hurairah for five years and heard him talking of Prophet Muhammd(PBUH)'s saying: The Prophets ruled over the children of Israel, whenever a Prophet died another Prophet succeeded him, but there will be no Prophet after me. There will be Khalifahs and they will number many. They asked: What then do you order us? He said: Fulfil the baya'a to them one after the other and give them their due. Surely God will ask them about what He entrusted them with.