Re: First wife's permission
Before going into discussion, we should recognise that in Islam, duty of someone is right of others and it is responsibility of state to safeguard people’s right (in other words, make people fulfil their duty towards other human)
Note: State has no right or responsibility to make people fulfil their duty towards their deity (Allah) ... but has responsibility that humans fulfil their duty towards other humans including family members’.
From my understanding of Islam ... informing existing wife and permission from existing wife is must, else a person is infringing a ‘contract trust’ and that is sin (as far as I know):
A: When only individuals are involved, state is indifferent: Informing existing wife (wives) of marriage intention and taking her consent (permission) is duty of husband and right of wife (wives).
Why?
In Islam, marriage is contract between a man and a woman to be husband and wife (they are both equal partners in this contract, with different rights and duties). By default, all situations of each other that exist at time of marriage can affect contract of marriage (if known) and thus are part of marriage contract, including existing marriages. Any additional marriage (after contract is made) affects life of wife (as well as husband) and thus previous contract made at the time of marriage changes. Thus, before one partner (husband) goes into further new contract of marriage, other existing contract partner (wife) should know and agree.
For understanding: In most cases marriage contracts (Nikah-nama) are made assuming that the girl would be only wife. At the time of marriage contract if would-be husband says that he intends to marry again later, overwhelming majority of time marriage contract would not happen for that man. Thus, even though this clause may not be written down at time of marriage but it is assumed as unwritten understanding of marriage contracts (just like consummation of marriage is not written down but it is unwritten understanding of marriage contracts). Any change to that understanding of marriage contract has to get agreed between concerned parties (husband and wife) before one party (husband) takes any one-sided step. Hence, informing and consent should be a must. Violation of that understanding without consent is infringing of marriage contract trust.
[Note: Life is full of contracts. Most contracts are made where understanding is part of contract. Rather most clauses in all contracts are based on understanding. If anyone violates that understanding it is always considered as infringement of contract and one can get sued for that too. For instance, simple contract like even renting a room in a house is full with clauses based on understanding. If one rents a room in house, house owner would expect that you look after the room and do not start breaking wall of that room, or that if you are provided with bed than you use it to sleep on it and should not start jumping on it or start using bed as wood for burning, or that if you move within house you should be clothed and not start roaming in house naked, etc, etc. Even in marriage, it is unwritten understanding that wife would not start clandestine relationship with another man and thus if she does, she infringes marriage contarct trust, etc, etc]
Obviously, if husband insist on second marriage without consent of wife, he can, as even though not marrying again is an undeclared understanding of marriage contract but it is not bonding (just like consummation of marriage is not bonding). Anyhow, in such situation, wife should know and should agree to stay in that contract ... else, if she desires, she can show two fingers to her husband, demand Khula and end marriage contract.
B: State’s involvement: Taking permission of second marriage from existing wife.
Husband does not need to take permission from his first wife of second marriage ... as usually, it is only an understanding but not written clause of marriage contract. If Husband thinks that he can do justice and treat both wives equally, he can go into second marriage contract. In such situation, if first wife is not in agreement he is taking risk of Khula, but he can still go ahead.
Anyhow ... In an Islamic state, it is duty of state (or ruler) to safeguard rights of individuals within state. If state could not safeguard rights of individuals than they are not fulfilling their duty, and (ruler) would be answerable on day of judgement. Hence, if state thinks that second marriage by a husband would infringe right of first wife than to safeguard themselves (fulfil their duty of safeguarding wife’s right), state can make laws forcing husband to take permission of first wife for second marriage before allowing such marriage to happen (as is the case in Pakistan).
If state makes such law, it becomes obligatory for Muslims within state to obey such law else they would be disobeying Allah and would be committing sin. Obey ruler (those in power ... or ... authority) is directed by Allah in Quran (4:59) and thus it is obligation of Muslims that they obey state (authority) unless state (authority) gives order for which state is not responsible (that is interfering with man and his ‘mamlaat’ (dealings) with his creator) or gives order that is in obvious contradiction with Quran.
