This question arises only when there is no Imam...
This question arises only when there is no Imam, either because no Imam exists at all or because the Imam is in occultation as is the case during our times. We should not mix up the question of Imamat with that of government and then ask what the Sunnis say in this respect and what the Shi'ah hold. As a matter of fact the question of the government is different from that of Imamat.
According to the Shi'ah, Imamat is a phenomenon exactly like that of Prophethood, and that too like the highest degree of it. As such we the Shi'ah believe in Imamat whereas the Sunnis do not. It is not that they also believe in it, but the conditions required for an Imam, according to them are different. Imam in Prophet Ibrahim's Progeny The verse which we now would like to quote clearly denotes the concept of Imamat in which the Shi'ah believes.
The Shi'ah maintain that this verse shows that there does exist a truth called Imamat, and that it has existed not only during the period following the death of the Prophet of Islam, but has been existing since the first appearance of the Prophets and will continue to exist in Prophet Ibrahim's progeny up to the Day of Resurrection. The Holy Qur'an says: "And (remember) when his Lord tried Ibrahim with His commands, and he fulfilled them, He said: I have appointed you an Imam for mankind.
Ibrahim said: And of my offspring? He said: My covenant includes not the unjust." (Surah al Baqarah, 11:124) Prophet Ibrahim's Trials - Command to Migrate to Hijaz The Qur'an itself has mentioned a number of trials which Prophet Ibrahim had to face. They included his struggle against Namrud and his henchmen who threw him into a burning fire as well as several subsequent events.
One of these events was that Ibrahim received an astonishing command which could not be implemented by anybody not fully devoted to Allah. The old man had no children. For the first time his wife, Hagar gave birth to a child at the age of seventy eight. Prophet Ibrahim receives a Divine command to go from Syria to Hijaz, take his wife and that child on the spot where at present Masjidul Haram is located and keep them there and then leave the place.
This command was not in keeping with any logic except that of complete self-submission and total devotion. As he was sure that it was a Divine command which he had received through revelation, he carried it out.