Was there a consensus of the companions (ijma al-sahaba) on the obligation of the khilafah (caliphate)?

In a Nutshell The consensus of the companions is a central and definitive proof of the obligation of appointing an Imam to rule the Muslims and call others to Islam, and the contention is rejected. Introduction There was a consensus among the companions that appointing a Khalifa is obligatory upon the Muslims.  This remained undisputed through Islamic history whereby jurists agreed  There is a clear consensus of companions upon the necessity to appoint an Imam Their consensus also shows that they considered appointing the Khalifa to be an utmost priority, which was prioritised over both the burial of the Prophet – peace be upon him – and the sanctity of life. The companions differed over who should be the Khalifa – a point which does not detract from its obligation and rather shows that the appointment of Khalifa is by choice and that it is necessity The ijma of sahaba upon the obligation of appointing an Imam is considered a definitive - proof Analysis There are 2 separate events which demonstrate the consensus of the companions that the Khilafa was an obligation. The first event highlights its obligation and priority and the second event highlighting that the issue of appointing the Khalifa and maintaining unity was an issue that was more important that the sanctity of the life of a Muslim.   The first event was the death of the Prophet – peace be upon him – which left the Muslims without a leader who would arrange their affairs for them now that the Messenger was no longer with them. The companions met at saqeefa bani sa'ida to discuss the issue of who would succeed the Prophet in ruling. The fact that they delayed the death of the Prophet (saw) until after this decision was concluded indicated the utmost priority that was accorded to the issue. Accordingly Sa'ad al-Din Al-Taftazani lists this ijma as the first and most important evidence for the obligation of appointing an Imam – stating that through their consensus it is shown to be the most important of obligations, and they engaged in appointing an Imam rather than first burying the Prophet (saw) الأول وهو العمدة إجماع الصحابة حتى جعلوا ذلك أهم الواجبات واشتغلوا به عن دفن الرسول صلى الله عليه وسلم This same phrase was also used by ibn Hajr al-Haytami, while he also adds the additional comment that the difference between the companions over who should be the Khalifa is not an evidence against the consensus of it being obligatory.   اعلمْ أنَّ الصحابة رضوان الله عليهم أجمعوا على أن نَصْب الإمام بعد انقراض زمن النبوة واجب، بل جعلوه أهم الواجبات حيث اشتغلوا به عن دفن رسول الله، واختلافهم في التعيين لا يقدح في الإجماع المذكور Al-Iji said that the consensus of the Muslims upon the obligation that it was not permitted to be without an Imam for any time has been transmitted by tawatur since the first era after the death of the Prophet (saw). This is proven by the companions leaving the most important act of burying the Messenger.  انه تواتر إجماع المسلمين في الصدر الأول بعد وفاة النبي على امتناع خلو الوقت عن إمام، حتى قال أبو بكر في خطبته: ألا إن محمداً قد مات، ولا بدَّ لهذا الدين ممن يقوم به، فبادر الكل إلى قبوله، وتركوا له أهم الأشياء، وهو دفن رسول الله ، ولم يزل الناس على ذلك في كل عصر إلى زماننا هذا مِنْ نَصْب إمام متَّبَع في كل عصر The second event was at the death bed of Umar, with the appointment of six from the companions to consult over who should be the next Imam of the Muslims after his death. He also left the instruction that if after 3 days anyone who was involved in the consultation that disputed the decision to be killed – an instruction upon which the companions remained silent; meaning that they assented even though the blood of a Muslim is protected in origin. From this a consensus of the companions can be derived that the unity of the Muslims and appointment of an Imam over them is obligatory. The historian Muhammad ibn Ashur in his rebuttal of the first contemporary denier of the obligation of the Khilafa who wore the garb of a scholar, Ali Abdul Raziq, wrote that the consensus of the companions was a qati (definitive) proof for its obligation. فلما تطلبوا الادلة القطعية وجدها في الاجماع و المراد من الاجماع اعلي مراتبه و هو اجماع الامة من العصر الاول استنادا للادلة القاطعة القائمة مقام التواتر و هو في الحقيقة مظهر من مظاهر التوتر المعنوي As for the argument that the short periods of time without an Imam between the death of the Prophet and the appointment of Abu Bakr, and the death of Umar and the appointment of Uthman are proof that the khilafa is not an obligation as mentioned by Qadi Iyad this is no proof at all, since they did not leave the position empty except that they were busy deciding who should be the next Khalifa to be appointed. لا حجة للأمم فى بقاء الصحابة دون خليفة مدة التشاور فى يوم السقيفة وأيام الشورى بعد موت عمر إذ لم يتركوها كرهاً، وإنما كانوا فى النظر فى تعيين الخلافة لـ إقامتها تلك المدة Conclusion The consensus of the companions is a central and definitive proof of the obligation of appointing an Imam to rule the Muslims and call others to Islam, and the contention is rejected.