Role of the khaleefah of the Muslims?
Question

                What is the role of the khaleefah of the Muslims?.
Praise be to Allah.
    Al-Maawirdi said, describing the tasks that the imam or ruler is obliged to do:
    There are ten things that he is obliged to do that have to do with public affairs:
    1 – He must preserve the religion according to its established bases and that on which the salaf of the ummah was unanimously agreed. If an 
    innovator or deviant or one who is confused about some issue emerges, he has to explain the proof to him and tell him what is correct, and deal 
    with him according to the set rights and punishments so that the religion will be protected against being undermined and the ummah will be 
    prevented from deviance.
    2 – He must judge between disputing parties and put an end to arguments so that justice and fairness will prevail, aggressors will not get carried 
    away and no person who is wronged will feel helpless.
    3 – He must guarantee public safety and security and protect the women and children of the ummah so that people can go about their business and 
    travel around in safety, with no danger to their persons or their wealth.
    4 – He must carry out hadd punishments so that the sacred limits of Allaah will not be transgressed and so that the rights of His slaves will be 
    protected.
    5 – He must reinforce the borders with equipment and forces so that the enemy will not find any opportunity to violate the borders of the Muslims 
    or shed their blood or the blood of non-Muslims living under the protection of the Islamic state.
    6 – He must strive in jihad against those who stubbornly reject Islam after being called to it, until they become Muslim or agree to live under 
    Muslim protection and pay jizyah, so that the rights of Allaah will be fulfilled and His religion will prevail over all others.
    7 – He must collect zakaah and charity money in the manner enjoined by the texts and scholarly consensus, without causing fear or being unjust.
    8 – He must work out what benefits etc are to be given to those who deserve them from the treasury of the Islamic state (bayt al-maal), without 
    being either extravagant or stingy; he must pay them on time, neither early nor late.
    9 – He must appoint people who are honest and sincere to different positions, so that things will be done efficiently and wealth will be kept with 
    trustworthy people. 
    10 – He should supervise matters directly himself, and check on things so that the ummah will be led in a proper manner. He should not rely on 
    delegating to others because he is too busy indulging in physical pleasures or worship, for he may end up delegating to a supposedly trustworthy 
    person who then betrays him, or a supposedly sincere person who then cheats him. Allaah says (interpretation of the meaning):
    “O Dawood (David)! Verily, We have placed you as a successor on the earth; so judge you between men in truth (and justice) and follow not your 
    desire * for it will mislead you from the path of Allaah”
    [Saad 38:26]
    Allaah did not allow him to delegate to others without supervising them or excuse him from that; He even described that as misguidance. Even 
    though these are the duties of the khaleefah as stated in religion, these are also the duties of everyone who has anyone under his care. The 
    Prophet  (peace and blessings of Allaah be upon him) said: “Each of you is a shepherd and each of you is responsible for his flock.”
    If the imam fulfils the rights of the ummah that we have mentioned above, then he has discharged his duty towards Allaah and to them, and so he is 
    owed the two duties of obedience and support, unless he changes.