Abu Bakr did not view the caliphate as an elective office; it is only natural that he appointed 'Umar his successor without prior consultation. Only after he had decided to appoint him, he asked 'Abd al-Rahman b. 'Awf and 'Uthman for their opinions. The former expressed 'Umar's well known harshness. 'Uthman more diplomatically answered that 'Umar's inside was better than his outside.1
Talha protested against the choice of him because of 'Umar's ill treatment of the people even during Abu Bakr's reign. Abu Bakr angrily rejected this criticism, declaring that 'Umar was the best of God's people.2 Abu Bakr owed him a considerable debt. 'Umar had made the coup at the Saqifa in his favor possible and had brought Medina firmly under control for him. Above all, in Abu Bakr's behalf he had deprived the Prophet's household (ahl al-bayt) of their legitimate rights.
When 'Umar came to power in 13/634, first he dismissed Khalid b. Walid and appointed Abu 'Ubayda as supreme commander of the Muslim armies in Syria. In Iraq, he commissioned Abu 'Ubayda b. Mas'ud Thaqafi with the general command. A year after Abu 'Ubayda b. Mas'ud was killed in battle, the caliph appointed Sa'd b. Abi Waqqas, the early Meccan Companion, as the supreme commander. Under Sa'd, the decisive battle of Qadisiyya was won, Mesopotamia was completely subdued, Kufa was founded and Iran invaded. When Abu 'Ubayda died in the plague of 'Amwas in 18/639, the caliph appointed Yazid b. Abi Sufyan governor of Damascus, Jordan and Palestine. Shortly afterwards Yazid, too, died of the plague, and 'Umar appointed his brother Mu'awiya b. Abi Sufyan as his successor and governor of Damascus.
'Umar made every effort to bring about the reconciliation with the Banu Hashim without compromising the essential right of all Quraysh to the caliphate. He thus treated 'Ali basically, like the other Companions. He displayed his favor for the Prophet's kin rather in courting 'Abbas who posed no political threat since he did not belong to the early Companions and had no personal ambitions. 'Umar also drew 'Abd Allah b. 'Abbas, who was too young to pose a political threat, near to him. Ibn 'Abbas was closely associated with 'Umar from the beginning to the end of his caliphate and he has left the most revealing reports about the caliph's private thoughts.
In a conversation he had with 'Umar early in his reign, he asked Ibn 'Abbas about 'Ali, and if he was still claiming his right for the caliphate. On Ibn 'Abbas's affirmative answer, he asked whether he claimed that the Prophet had designated him. Ibn 'Abbas replied yes, adding that he had asked his father about the truth of this claim, and 'Abbas confirmed it. 'Umar commented that there had been some words of the Prophet in respect to 'Ali. The Prophet had deliberated about this matter for some time, and during his illness, he intended to name him clearly, but he, 'Umar, had restrained. If 'Ali were to assume the caliphate, the Arabs everywhere would revolt against him. The Prophet had understood what these motives were and had therefore kept silent.3
On another occasion, Ibn 'Abbas narrated, 'Umar remarked to him that his companion, 'Ali, was indeed the worthiest (awla) of people to rule after the Apostle of God “but we feared him for two reasons”. When Ibn 'Abbas asked him eagerly what the reasons were, he mentioned his youth and his love for Banu 'Abd al-Muttalib.4 Ibn 'Abbas also narrated that once, 'Umar came, late at night, and told him to go out together and guard over Medina.
He was bare footed and his whip hung down his neck. They went on as far as Baqi' al-Gharqad. There 'Umar fell on his back and sighed deeply. He asked 'Umar, “O, what can worry you, Amir al- mu'minin?” He answered, “The cause of God. O the son of 'Abbas.” He uttered if he let him, he could tell what was running through his mind. 'Umar accepted and told him to think it over and added what he (Ibn 'Abbas) had said him before had all been right. Ibn 'Abbas told him that he ('Umar) was thinking about his successor.
He named some eminent Companions and asked 'Umar's opinion about them. About 'Abd al-Rahman b. 'Awf, he said that he was a parsimonious man, but the office of caliphate needed someone thrifty without miserliness and generous without extravagance. On Sa'd b. Abi Waqqas, he said that he was a valiant fighter on horseback, but unworthy to command. Then he said that Talha b. 'Ubayd Allah was a greedy and vainglorious man; al-Zubayr b. 'Awwam was a battle hero, but occupied himself in haggling in the markets of Medina; 'Uthman b. 'Affan would give the Banu Abi Mu'ayt power over people, the Arabs would certainly disobey him and 'strike his neck'. Then he fell silent.
After a while, he asked Ibn 'Abbas, “Do you think 'Ali b. Abi Talib is worthy of caliphate?” He answered, “On account of his early merits, his knowledge and his close kinship to the Prophet why he should not be worthy of caliphate.” 'Umar replied, “By God 'Ali is, as you said, worthy of caliphate, but if he rules he will lead the people on the right path that you know, except that he is lighthearted and young.” Ibn 'Abbas said ''You did not consider him young on the Day of the Trench. When 'Amr b. 'Abd Wudd came out, panic seized the warriors and the old retreated; and on the Day of Badr while he cut the enemies' heads off and no one advanced him.”
'Umar said, “O Ibn 'Abbas it is enough.” He fell silent lest he would make the caliph angry. Then 'Umar continued, “O the son of 'Abbas, your cousin ('Ali) is the worthiest of all, but he would lead you on a path, in respect to what is right, which you know. If he does so, his swear of allegiance will be broken and people will fight him.”5
During the ten years of his reign, 'Umar was anxious to keep most of non-Arab Muslims out of Arabia, in particular Medina. The strong bias against non-Arabs in 'Umar's policies eventually contributed to creating the atmosphere in which Abu Lu'lu'a the Persian slave of Mughira b. Shu'ba was prepared to assassinate him in a suicidal attack6 and in which the Caliph's son 'Ubayd Allah was equally prepared to murder any non-Arab whom he could reach.7
The Caliph's resolve to leave the choice of his successor to a council (shura) among the most eminent early Companions was no doubt firm long before Abu Lu'lu'a mortally wounded him. The electoral council consisted of six members: 'Ali b. Abi Talib, 'Uthman b. 'Affan, 'Abd al-Rahman b. 'Awf, al-Zubayr b. 'Awwam, Sa'd b. Abi Waqqas and Talha b. 'Ubayd Allah (who returned to Medina only after the election of 'Uthman, and Sa'd officially acted as his proxy).
'Umar assigned Abu Talha b. Zayd b. Sahl Ansari to supervise the electoral council. 'Umar ordered him in case four of them agreed on one man and two of them disagreed, he should cut off the heads of those two who had disagreed. If three of them agreed and the other three disagreed, he should cut the heads of the three whom 'Abd al-Rahman b. 'Awf was not included. If it passed three days and they did not consent to anyone, he should kill all of them.8 An important part of the decision in favor of 'Uthman was due to the latter's brother-in-law, 'Abd al-Rahman b. 'Awf.9
'Umar considered 'Abd al-Rahman, 'Uthman, and 'Ali as serious candidates for caliphate. 'Abd al-Rahman, however, did not aspire to supreme power and took him out of the competition in return for being recognized as the arbiter between the candidates. Since al-Zubayr and Sa'd equally did not press their own or Talha's claim, only 'Uthman and 'Ali were left. 'Ali reminded them his own case as the closest kin to the Prophet (S.A.W.A.) and his early merits in Islam, but the composition of the council was on the behalf of 'Uthman and caliphate suited him down to the ground.