I'm going to assume that I know what Dally is getting at here – and it isn't specifically whether I (or others) agree with the church leaders who have commented.
Religious organisations have as much right to comment on any subject as any other group in society – business, financial, NGO, etc – let alone any individual.
It becomes an issue if they either try to attain their wishes by underhand means, such as using emotional blackmail.
The latter has been the case in recent years when abortion and equal adoption were being debated, and the Catholic church in the UK, together with Catholic adoption agencies, attempted just such a tactic. There were threats to excommunicate Catholic MPs who voted the 'wrong' way, for instance, plus threats of closing Catholic adoption agencies if the law was changed to allow gay couples to adopt.
In the former example, it is saying, in effect, that an individual MP must subjugate the wishes of their constituents, as perceived via any manifesto, to the private beliefs of the individual MP. That would be utterly counter to our notions of democracy.
There were accusations of a Catholic 'cabal' operating within the Labour government – some of which seems to have credence simply because there were, for instance, an awful lot of people from such a belief group having a high-profile involvement with the legislation on extreme porn, for instance. As an individual who contributed to the consultation on that legislation and attempted to get articles published on the subject, I was aware of a lot of things that were not obvious. The religiosity of the MPs sponsoring the bill was one, as was the similar religiosity of many of the senior civil servants involved – the latter information came to me courtesy of the Spanner Trust.
There were also questions over the impartiality of the likes of Opus Dei and Cabinet member Ruth Kelly in terms of what was most important to her: the will of the constituents who elected her (and the government as a whole) or her individual religious beliefs.
It seems, in this case, that such things are not occurring. As far as I know, Soon-to-be-Cardinal Vincent Nichols has not said to Iain Duncan Smith, a Catholic, that he will be excommunicated if he doesn't treat the poor more as the clergyman would like.
If he had, then much as I personally detest the liar IDS, Nichols would be bang out of order – irrespective of my own view on the subjects of welfare, austerity etc.
As to whether religion and politics should mix – well, that's remarkably similar to the views that one used to hear about sport and politics. That was often as a sideways comment on the anti-apatheid campaign, but the truth is that sport and politics have never been separate. Indeed, Rugby League fans should know all too well the involvement of politics in sport, since it was involved in the creation of the game – and the approach to it from the Establishment for a century thereafter.
Religion is no different: it has always been political and always been involved in politics.
Whether we like it or not, Thomas Mann's dictum holds true: "Everything is politics".
And in many ways, our attempts to place politics into a sphere away from other areas of life is part of the problem with the state of public discourse in the UK today.
At present, it seems that the comments from religious leaders are from those within Christian churches.
in terms of the legitimacy of their concerns, I would suggest that Christian theology is rather more closely on their side over this issue than it was over, say equal marriage or even abortion. In this case, they don't need to rely on interpreting Old Testament scripture for a view, but rather, on taking the reported comments of the man who is central to their religion, via the Sermon on the Mount, the Beatitudes etc.
One wonders if they'll start quoting Matthew 19:24 sometime soon.