Thats where democracy steps in ! Come up with a narrative & then place it before the people...if they agree its get constituted into law, if not then we go back to the drawing board or someone else gets the vote.
Why does one need unanimity ? If I have a certain point of view & I place it before a million people as part of my party's manifesto or 'white papers' *are they called ?* & let the people decide whether they agree with such an interpretation. Just like such is the case with every other thing ! Principally speaking think of the Shariah as the Islamic equivalent of say the Swiss Civil Code...let the people decide between them ! Never...ever impose it the way Zia ul Haq did !
And this - the democratic process - is the only way for how else does one decide 'issues' on a collective level if not by letting the most heads prevail ! The assumption being here that people cannot agree in error like this because collective wisdom will prevail. If they want a Secular Pakistan, an Islamic Pakistan, an Islamist Pakistan, a Taliban styled Pakistan, an Iranian styled theocracy, a Maoist Pakistan, a Kingdom of Pakistan - Let them decide ! Let them decide...! It doesn't for a second imply that the decision is final & absolute or even 'correct' all it means is that at a 'collective' level the human race has yet to come up with a better system that brings about the ownership of a decision of as much of the People as possible & people's ownership equals a better received response. Furthermore because minorities cannot be ignored & at that large minorities there will always be compromise to bring them on board & at the end a consensus of as many different people as possible will be reached. That, in my opinion, is the only way forward.