From the Shi’a point of view, Wilayah Faqih during the occultation of Imam Mahdi is the continuation of the Wilayah of the infallibles; meaning that during the absence of an infallible Imam, the responsibility of administrating and managing the affairs of the Islamic society should be carried out by the jurists. This authority has been granted to all jurists; however, when one of them establishes a government, the others must obey him and are no longer allowed to interfere in affairs and decisions pertaining to government. At the same time, we must distinguish between being most learned in the field of “Wilayah Faqih” and “Marja’iyyah”. The most learned in “Wilayah Faqih” is one that not only has the ability of ijtihad, but is also aware of international and domestic affairs and circumstances; an individual that can recognize the plots of the adversaries of Islam and can make decisions at the right time. Accordingly, Grand Ayatollah Khamene’i has been recognized by the decisive majority of the members of Khubregan (The Assembly of Experts) as the most appropriate individual for this position.
The word “Wilayah” in Arabic is derived from the root word “وَلى” (Walaya). This root word, according to great Arabic literature experts, only has one meaning. The root word ”Walaya” means closeness and kinship. In Arabic, three meanings have been mentioned for the word “Waliyy”: friend, liker and helper and for the word “Wilayah”, in addition to the three abovementioned meanings, two other have been mentioned: domination of the leader and domination of the government. In Farsi, many meanings have been attributed to the word “Waliyy” such as friend, companion, owner, protector and someone who has been granted authority in regard to a certain issue. For the word “Wilayah” the meaning government has been mentioned.
From the Shi’a perspective, Wilayah Faqih during the occultation of the final imam (aj) is the continuation of the infallibles’ Wilayah, the same way their Wilayah is the continuation of the Prophet’s. Wilayah Faqih is the belief that the person leading the society and administrating its affairs must be learned in Islam’s teachings. Therefore, if an infallible Imam is present, he will be the leader; otherwise, this burden will be carried by the jurists. This theory is a result of accepting the point that the main responsibility of a government, from Islam’s point of view, is to promote divine laws and values within the society, and in order to do so, there must be a person that is learned in the teachings of Islam at the highest decision making position. Of course, this person must also be aware of foreign and domestic issues and he must possess the ability to administrate affairs and manage the society.
Sheikh Saduq, through an authentic chain, narrates from Ishaq bin Yaqub that he said: “I asked Muhammad bin Uthman Umri (the second specific representative of the Imam of our time in his minor occultation) to get a letter I had written inquiring about certain complicated issues to the imam and in my response, I got this letter with the handwriting of the imam himself; one of the passages of the letter is as follows:…و اما الحوادث الواقعة فارجعوا فیها الی رواة حدیثنا، فانهم حجتی علیکم و انا حجة الله علیکم......" which translates to: “As for the issues that come up, refer to the narrators of our hadiths, for they are my hujjat upon you, and I am the hujjat of Allah upon you.
Muhaqqiq Karaki says: All Shi’a (scholars) agree that a just, trustworthy Faqih (i.e., jurst) that possesses all qualifications of issuing Fatwas, who is referred to as a Mujtahid, is the representative of the infallible imams in all fields in which their authority can be possibly passed down to a representative.
In response to the second and third part of your question, we must shed light on a few points:
In the Shi’a culture, Marja’iyyah is a mixture of issuing Fatwas and authority and throughout history, the great Maraj’i would guide and lead people in regard to both general divine rulings and specific social issues. They would even play the role of judges on certain occasions. Also when distinguishing between Marja’iyyah and leadership, we must explain that a Faqih assumes the responsibility of leadership to administrate the Islamic society according to religious standards and values, while “Marja’iyyah” refers mainly to issuing religious Fatwas and slight social guidance.
Therefore, the key factor in the Marja’iyyah of a Faqih is his expertise and ability to extrapolate and draw religious rulings from Islamic sources, while the key factor in leadership, in addition to ijtihad, is his ability to administrate the society according to Islamic values and standards.
In light of this, it is possible that a certain Faqih is preferred over another because of his greater ability of extrapolating rulings, but the latter is preferred in terms of leadership due to his ability of administrating the society.
In an Islamic political structure, the issue of leadership and Wilayah Faqih can be portrayed in two ways:
First: The leadership of the Islamic society is carried out by an elite group of jurists in the form of an assembly; this is if all of the qualifications of leadership are not possessed by one individual.
Second: In a situation that all the qualifications are present in one person; meaning that in addition to the quality of ijtihad (The ability to draw rulings from sources), he also possesses other qualifications of leadership, the Wilayah and leadership will be entrusted to one Faqih.
Knowing that the issue of leadership and administrating the Islamic society is directly related to the society’s order and that the multiplicity of decision-makers causes disorder, it is necessary that the leader be only one person, especially since, from Islam’s perspective, there are no separate Islamic countries and all Islamic lands are one united country.
We must also pay attention that the position of governmental authority and power, which is the authority to rule and administrate the country and implement the rulings of the Shari’ah, has been granted to all Jurists, but if one embarks on establishing a government, it is mandatory for all the rest of the jurists to obey him and it is impermissible for them to intervene in affairs and decisions of the government and cause problems for the leader. Proof for this claim is that the true Waliyy is Allah and his tenets, and even the prophet executes divine law because of Allah’s command as the Almighty says in the Quran: “لتحکم بین الناس بما اریک الله” “You have been sent to govern over people (but not any way that you wish,) but rather in the way Allah has shown you through the revelation.” Therefore, in an Islamic government there is only one “Waliyy”, that is Allah and his religion, no one can add anything to it and no one can omit anything from it. Accordingly, the Islamic leader only leads because of his religious aspect and characteristics such as ijtihad, management and justice, which means that the indirect Waliyy is still Allah.
As for the part of your question in which asks: “Now that there are many other Jurists, why should Ayatollah Khamene’i be the Waliyy Faqih?”, we must distinguish between “Al-A’lamiyyah” (Being most learned) in Wilayah Faqih and in Marja’iyyah. In other words, what is referred to as being most learned in “Wilayah Faqih” is not the same as being most learned in “Marja’iyyah. Imam Ali stated: “ایها الناس ان احق الناس بهذا الامر، أقواهم علیه و أعلمهم بامرالله فیه” O people! The most appropriate person for this matter (Wilayah and Government) is the one who has greater ability in this field and is most learned in regard to Allah’s commands about leading the society. Therefore, what is meant by “Al-A’lam” in Wilayah Faqih is not only being most learned in Fiqh and Islamic rulings, but rather being most learned and aware of domestic and international affairs; the Waliyy must be able to scholarly apply divine rulings to the different situations that the society encounters. He should also be able to recognize the plots and schemes of the enemies of Islam, make decisions at critical moments and take action accordingly.
It is mentioned in the hundred and seventh article of the Iranian constitution that: “After the demise of the eminent Marja' al-Taqlid and great leader of the universal Islamic revolution, and founder of the Islamic Republic of Iran, Ayatollah al-'Uzma Imam Khomeini who was recognized and accepted as Marja' and leader by a decisive majority of the people, the task of appointing the leader shall be vested in the experts elected by the people.” The Assembly of Experts, which is comprised of Islamic experts that are chosen by the people, assumes the responsibility of identifying the Faqih that possesses the required qualifications for leadership.
During different periods, the members of this assembly may identify different individuals as the leader. However, at this point, Ayatollah Khamene’i has been chosen and introduced to people by the decisive majority of this assembly as the most appropriate person for this position due to possessing the ability to administrate the affairs of the Islamic government.
In addition to this, the great Imam Khomeini’s emphasis on his merits and qualifications for leadership has been mentioned by Hujjat al-Islam Hashemi Rafsanjani in the presence of the members of the Assembly of Experts: “Among you is a person that is qualified for leadership and you will not reach a dead end (not have a solution).”
It also said that the late Hujjat al-Islam Seyyed Ahmad Khomeini (the son of Imam Khomeini) mentioned that Imam Khomeini once stated: “He (Ayatollah Khamene’i) is qualified and appropriate for leadership.”
To answer the question in regard to Grand Ayatollah Fazel Lankarani’s fatwa, we must briefly explain the difference between the concepts of “Fatwa” and “Hukm”:
Fatwa is defined as follows: the result of a Mujtahid’s referring to religious sources in order to draw the universal rulings of religion in regard to a certain field; this result is only applicable for his Muqalledin (Followers of a Marja’).
However, a “Hukm” is when the leader recognizes a certain act as the responsibility of all Muslims, a group of them or a certain person, according to the general rulings of Islamic law, Islamic systems and examining the contemporary situation.
From Allah’s perspective, acting according to the Fatwa of a Faqih that possesses the qualifications of issuing Fatwas is obligatory, the same way obeying the command of the leader and the Waliyy is mandatory, with the slight difference that acting according to a Fatwa is obligatory for the Mujtahid and his followers while obeying the commands of the leader is obligatory for all Muslims.
For more information you can refer to the following books:
1- Wilayah Faqih, Imam Khomeini.
2- Wilayah Faqih in the Islamic Government, Tehrani, Seyyed Muhammad Hussein.
3- Wilayah Faqih, Ma’refat, Muhammad Hadi.
4- The Wisdom behind the Governance of the Faqih, Mamduhi, Hassan.
5- Wilayah and Religion, Hadavi Tehrani, Mahdi
 See: Maqayis al-Lughah, vol. 6, pg. 141; Al-Qamus al-Muhit, pg. 1732; Al-Misbah al-Munir, vol. 2, pg. 396; Al-Sihah, vol. 6, pg. 2528; Taaj al-Arus, vol. 10, pg. 398.
 Some scholars have denied the meanings of friendship and assistance for the word Wilayah and have only mentioned the meanings of governing and leadership.
 See: Al-Qamus al-Muhit, pg. 1732; Taj al-Arus, vol. 10, pg. 298; Al-Misbah al-Munir, vol. 2, pg. 396.
 Hadavi Tehrani, Mahdi, Velayat va Diyanat, p. 64
 Velayat va Diyanat, The Reasoning behind Wilayah Faqih, logical reasoning.
 Wasa’el al-Shi’ah, vol. 27, p. 140
 Wasa’el al-Shia, vol. 27, pg. 140.
 For information on the discussions regarding this narration, see: Velayat va Diyanat, pp. 94-102.
 Quoted from the book Mabaniye Mashru’iyyat dar Nezame Velayate Faqih, Kavakebian, Mustafa, pg. 68.
 Hadavi Tehrani, Mahdi, Velayat va Diyanat, pg. 138.
 Velayat va Diyanat, pg. 141.
 Velayat va Diyanat, pp. 140 and 141.
 Velayat va Diyanat, pg. 142.
 Javadi Amoli, Abdullah, Velayate Faqih, pp. 256 and 257.
 Bihar al-Anwar, vol. 34, pg. 249.
 Javadi Amoli, Abdullah, Velayate Faqih, pg. 231.
 Hashemi Rafsanjani, Ali Akbar, (interview) Keyhan Newspaper, (Monday 20/11/1382).
 Hadavi Tehrani, Mahdi, Velayat va Diyanat, pp. 139 and 140.