The opening of the farcical (probably intended as such) "negotiations" between powerless pro-Taliban negotiators selected by the government of Pakistan and equally powerless pro-Taliban negotiators selected by the Taliban (2 of their representatives, including cricket star and political buffoon Imran Khan, have already dropped out) has led to a rash of TV appearances by various luminaries discussing the suitability or otherwise of the Taliban's demand that "Western Democracy" be replaced by the "Islamic System" in Pakistan. In this debate the Islamists obviously have a huge advantage, in that the founder of the state promised a state "based on Islamic ideals" where there will be "nothing but Quranic principles as our constitution", the first constituent assembly duly passed an "Objectives resolution" that states that Pakistan will be a state where Muslims can live "in accordance with the teachings and requirements of Islam as set out in the Holy Quran and the Sunnah" and the current constitution includes detailed "Islamic" provisions including the statement that no law shall be repugnant to the holy quran and sunnah. Still, there is some wriggle room in that the anti-Islam panelists can raise the question of "whose Islam" and thus defer the enforcement of Quran and Sunnah till such time as agreement can be reached about what it is that the Quran and Sunnah actually require of us. In the interest of the infidels and unislamic panelists, I want to point them towards a more substantive argument: The Shariah as traditionally understood (and various left wing Iranian jokers notwithstanding, there IS no other shariah yet) simply has NO POLITICAL SYSTEM.
No details about division of powers, method of selection of ruler, transfer of power, institutions of the state, etc etc. Nothing. Nada. There is no there there. If shariah is the set of rules and laws put together by the jurists of the four madhabs of Sunni Islam (nobody pretends that Pakistan is about to enforce some sort of Shia shariah, so that is besides the point) then they are practically nothing except detailed rules of inheritance, marriage laws and few penal regulations (regarding robbery, adultery, alcohol, murder but not, for example, about rape or transporting banned drugs across state lines). There are, of course, endless arguments about minor rules of social and personal conduct and hundreds of volumes of conflicting fatwas about farting during prayers and prayers to be said before and after sex.
But there is practically nothing about the political system or the constitution of a modern state. Any ruler and any state arrangement is OK as long as it is nominally Muslims and enforces the above rules for its Muslim population (and some humiliating ones for its non-muslim population). Once this is made clearer, we can proceed further.
Unfortunately for the infidel panelists, where we proceed next is also troublesome. It will turn out that while the constitution of Pakistan (or ANY other constitution) is more or less kosher as far as division of powers, elections, parliaments and supreme courts is concerned, the shariah DOES have a few rules about alcohol, amputation of hands and conversation with women.... and those rules are not being enforced in Pakistan.
Back to square one.
On a more serious note, i highly recommend Carl Brown's Religion and State; the Muslim approach to politics. Must read. https://www.goodreads.com/book/show/2074197.Religion_and_State