You are again talking about secularism, in Quran there is no such thing as to change the constitution by 2/3 majority, you keep mixing Quran with secularism, you must stop making mischief and learn to know Quran and not secularism rule mix with Quran, calling ne innocent sarcastically is not nice, A good Muslim will never be sarcastic to other Muslim.
Either you have democracy or khalafat. If you have democracy you have authority to change constitution by 2/3 majority. (either change it to islamic, hindu or secular law).
In khalafat quran is rule of law and khalifa is bound to it.
First decide what do and zaid zaman hamid want.
By the way can you show me reference where he talked about quran as constitution. Can't find that part in his speech.