Of course Sharia courts of some description may have some place in resolving property disputes where this is mutually preferred by the parties - maybe this is what the Archbishop meant, but this is quite non-controversial and really not worth the bother of stating as though it were a great truth.
The Archbishop's remarks have however rightly been described as muddled and unhelpful.
The kernel of the Archbishop's thinking was stated in his reaction to the furore about the sexual orientation regulations and the issue of the campaign for an exemption for Catholic adoption agencies.
His thinking was that in a state that makes space for religious belief the state shouldn't claim total allegience of religious adherents and there should be a plethora of arrangements, special laws, separate courts, conscience clauses to make religious believers feel happy within a secualr state.
Now this idea isn't one of religious fundamentalism, where the sect seeks a kind of imposition of religious belief upon non-believers, but it is far from satisfactory nonetheless.
It inevitably leads to fears of individuals in faith communities setting themselves apart from and above the law and this is particularly dangerous where the laws are ones protecting human rights and outlawing discrimination - and here we basically end up with a self awarded right to be above the law of the land.
The Archbishop made a mistake in other ways as well. Muslims didn't ask him to make huimself their spokesperson and I don't think the reaction has spread awareness and understanding of different commun ities. Plus I don't think that he is that much of an expert on the subject of Sharia.
A much stronger argument might have been that we need to find ways of allowing the devlopment of Sharia in different countries that can incorporate human rights and considerations of freedom and equality in a way that could challenge the less enlightened forms in many of the countries where it is practised. This wasn't, however, the point he was trying to make.
And this might have led to a reflection (in that very involved and intellectual way beloved of the Archbishop) to a reflection on the interaction between Christianity, the law and rights and protections of others, though the results would have been opposite to the veiw he espoused when he proposed making religious believers exempt from discrimination law.
Ultimately therefore a very big mistake - in timing, content, argumentation and political nouse (or lack thereof).
He's been roundly condemned because his idea's a dud, whichever way you look at it.