Dr. Muzammil H. Siddiqi, former President of the Islamic Society of North America, states: Leadership in Islam is based on knowledge and piety. Leadership is not hereditary. Any person from any background can be chosen as a leader as long as that person is God-Fearing and qualified for the job. The best example is the example of the Imam in our daily prayers. The Prophet (peace and blessings be upon him) mentioned that the person who deserves to be Imam is the one who is the most knowledgeable about the Qur’an. If all people are equal in the knowledgeable about the Qur’an, then the one who is the most knowledgeable about the Sunnah should lead. If all are equal in knowledge of the Sunnah, then the one who made Hijrah first. If all are equal in that, then the one who is the most senior among them should lead. This is just an example of choosing leadership and setting priorities in doing so. In a similar way, priorities can be established in other areas where the leadership is required.
Concerning the issue of doctrine and the sources of truth and who has the right to interpret, the doctrines have basically been given in the Qur’an and the Sunnah. These are our main sources of truth. Those who have good knowledge of the Qur’an and the sunnah have a right to interpret these methods. The scholars in the community in general will see their interpretations. If their interpretations are valid, then they will be accepted. The final authority is the Qur’an and the Sunnah.
how Islamic faith handles changes. Islam has the principle of ijtihad to meet the challenges of changing times and circumstances. If there is a change in circumstances, ijtihad can look into that and can give the direction accordingly. Finally, your question about secular and religious authority, there is no separation between secular and religious in Islam. Everything comes under the rules of Allah. So any authority whether it is secular or religious, if it violates the rules of Allah, then it will be criticized and corrected.