Ibn Abd Rabbeh writes in his famous book, Iqd-ul-Farid (The Unique Necklace), Volume II, page 203, that many years after Muawiya was firmly established on the throne, and had consolidated his position as the khalifa of the Muslims, he posed, one day, the following question to one of his courtiers:
Muawiya: You are a wise, intelligent and knowledgeable man. I would like to know what in your opinion, exactly, was the cause of the civil wars of the Muslims.
The Courtier: The murder of Uthman.
Muawiya: No.
The Courtier: Ali's accession to the throne.
Muawiya: No.
The Courtier: Then I will request the Commander of the Faithful to enlighten me in this regard.
Muawiya: Well, I will tell you what was the real cause of the civil wars of the Muslims. All the conflicts and civil wars of the Muslims had their origins in the electoral committee which Umar appointed to choose a khalifa.
Muawiya was right. The seeds of civil war in Islam were planted on the day when Umar picked out the members of his electoral committee. Instead of one candidate for caliphate, he made six candidates. If his decision to appoint his successor had been as direct and forthright as that of Abu Bakr had been, Islam might have been spared the traumatic and horrendous experience of civil wars so early in its career. The Muslims who fought against and killed each other in these civil wars, did not belong to the distant future; they belonged to the generation of the Prophet himself.
Civil wars broke out in Islam at a time when its idealism was supposed to be still fresh. But the elective system devised by Umar had built-in confrontation, and it took Islam across a great divide. His policy proved to be counter-productive, and his mode of giving the Muslims a leader through his panel of electors turned out to be one of the greatest misfortunes of the history of Islam.