Simple, in a Shariah law, can a non Muslim be head of the State, your Khalifah/ xyz?
If not, then I cannot support such a system.
There is no provision for the head of state status in the Quran.. The Sharia in the Quran has no specifications for it.
The rest is all inference and nothing more.
If the state is a Muslim state by majority then it makes sense to have one leader FROM the majority. And this is from a purely religious perspective and nothing to do with race or caste or otherwise.
However, that also implies that Muslims would prefer a leader from their community as a head of state.. and by head of state we do not infer the rather ceremonial role given to presidents in our parliamentary system but that of the Prime minister. This begs the question, why is a non-muslim not allowed to lead an Islamic state(
whose concept is still totally unclear as all interpretations of it are drawn from 6th century Arabia till the next 100 years or so..after which the system deteriorated into the usual dynastic system). So if it truly was a "perfect" system for all times then it would have lasted much longer than this; giving the impression that leadership has more of a role in a Sharia state than the system derived from it. Hence the system itself has never been "set in stone" and can evolve to meet the times.
Then lets reassess whether there is anything as such as a "shariah" state? Or is the idea of the Sharia laws being confused with a state. Sure, laws form the constitution of the state but you cannot run a state only on civil law. You need to have a definition of a system and how it is to be run, be it a dynasty, a democracy, a dictatorship and so on. The only condition laid down in the Quran for all these system of rule are that of ensuring that the Shariat (for a layman
examples of behaviour and repercussions for transgression) are followed in this system.
So what then is the whole hullabullo about the Islamic state and the system. Well, in essence the idea of Pakistan was the Islamic state. The laws of Shariah were to be integrated for the Muslims while the rest of the minority had existing civil laws. The democratic parliament with its electoral system would ensure that 3-4 cycles later the people would eventually learn to elect competent leadership. The 73 constitution was tainted by the Mullahs from the get go for their own gain, but essentially is a well defined structure for the running of a Muslim majority state as the Muslims of the Pakistan area wished according to the times(Level of literacy, poverty, access to welfare etc). If these conditions change, then the system has to evolve with it.
The legistature should in theory ensure that.
However, the democratic system has one essential flaw. It only throws out the average of the population and favors the shrewd. Their intentions are essentially irrelevant in the systems ideals until or unless public information and awareness along with the will to govern themsleves exists. For the reigion that is Pakistan which has generally been under feudal or princely rule.. this is difficult to extract within a 100 years, let alone 67 without the leadership of the intellectuals of the society who can create or wield power. Since the last items role has been sketchy as best, the result is clear to see.
One then asks, how is Pakistan and its systems and its story still relevant to the basic question of Shariah and its role?
Well, the story of Pakistan is essentially an exemplar as to why at the end.. regardless of the well natured and well meaning non-muslims who have assisted Muslims from the time of the Prophet; Muslims are the only ones who can only ever truly be sincere AND be completely in sync with the wishes of the Muslims at the same time. Be it the Khilafat movement, or the Congress government in the 30s... time has proven that despite the well wishes of many Muslim and non-Muslim leaders to crate a United state and maintain the Unity of the inhabitants of the subcontinent, it is impossible to satisfy a significant majority and a significant minority at the same time especially where the issues of religious tolerance and that of a lack of education is concerned(although recent behaviour of Internet Hindus in the 2014 elections shows that education makes little difference in tolerance). Essentially, Muslims on the whole want what suits them, Hindus will want what suits them.. and bobs your uncle. That begs the question, look at the Sikhs..they seem to be happy either way.. or did I miss 1984. But then, I did not miss the level of integration and respect that is given to Sikhs post partition(and except for the brief period in 80s) the Sikh community was not prosecuted by targeted means by a section representing the majority nor is it complaining of defaced worship areas or murdered computer technicians in Pune.
How is that even relevant to the question again? Well, each of these cases shows that regardless of the good intentions of a Muslim or a Non-Muslim in a Islamic state, each will not be best able to represent the aspirations and ideals of the community of the other with true cohesion or connection, without being either demonized by their community or even that of those they represent. Gandhi never truly connected with the idea of Khilafat movement as he perceived it differently.
Which is why, a non-Muslim, regardless of their intent and education in Islamic theology; will never be able to connect or be accepted by Muslims in many issues, the same way someone like Zakir Naik will never be taken seriously even if he goes all out defending Hinduism in some context.
But that is the aspect of religion, what about the aspect of statehood, of diplomacy and so on. Well, one has to realize that as the concept of the state's system is fluid, so is the idea of the leadership. It may have one decision maker, but it does not mean that his decision comes from whatever he wishes. Perhaps the idea of Plato's republic may suit a state like Pakistan best. After all, experience shows that a dictatorship or an answerable to no one leadership has failed miserably in Pakistan and led to ruin;yet the same seems to be working well in Oman. This brings me back to the point I raised in my first paragraph. The system is only as good as the leadership it begets, and that leadership is what makes the system work well. One can then cite as a refute that countries such as the US and other states have leadership from different communities and find good representation..but Ill ask this then, why did Obama receive a large percentage of the african american vote? What was the deciding factor in their voting ideals?
In conclusion then(or rather not), the idea of a non-muslim ruling a Muslim state has less to do with Sharia, and more to do with Human nature. India would form a large "I object" to this theory with the previous government with a Sikh PM, but the 2014 elections and the resounding behaviour of the largest religious community seems to belie that and support that facet of human nature: that you will always look for someone that represents your best interests from your own kin.
Disclaimer: I may be wrong in my opinion, but then my opinion is open to educated corrections and not copy paste rhetoric.