I don't know how weird this sounds but....:
"Protect the girl that wants to wear the headscarf; and protect the girl that does not want to wear it"
While ideologically a proper Islamic country would be free from bigots and proper Islam would be practised and all minorities would be state protected and free to practise what ever they wish as long as it doesn't interfere with the State or cause corruption; however this is very hard simply because we seem to have not many sane people with proper Islamic knowledge and chances are we muck up as very high, so it's not really happening.
That's why I say a mixture of both Islamic and Secularism should be implemented; because honestly this mix is probably closer to the true Islam and not the bigoted version.
Full secularism, on the other hand, for most obvious reasons, can't be implemented.