Churches have little to do with religious belief. They are worldly organisations seeking to expand their wealth, power and prestige. Some are criminal businesses: most obviously, the churches founded by American evangelists in pursuit of personal profit. At best churches are like political parties, seeking to enlist (and sometimes browbeat) support for favoured causes.
They need to be kept in check.
They are always claiming privileges which a decent state will deny. Like a political party or a limited company, their finances should be transparent.
There should be no tax break deals like those only recently done between Berlusconi and the Church in Italy: I give you the tax breaks and you don't criticise me. No problem, Signor B.
There should be no Vatican state-like entity able to hide its affairs behind a bogus claim to statehood, courtesy of Mussolini: I give you a state and you don't criticise me. No problem, Duce.
They should be kept out of state-funded schools. Those should be a place where children are educated, not indoctrinated. If parents want supplementary schooling for their children, then they can seek it out of school hours in Saturday schools and Sunday Schools. Few would want it.
The lust for children under seven (as the Jesuits formulated it) is the one which democratic states should most firmly resist.
As significant employers, churches should be held to labour market legislation. That means equality of opportunity. It means that there should be no onerous conditions irrelevant to the discharge of duty: some priests will choose to be celibate but it should be illegal to demand it of them. Full stop.
Their activities should be overseen in the same way that other large businesses are overseen. There should be an OfChurch. When churches are hit by scandals, they should end up subject to probing public enquiry, before Parliament and before a Judge, just like News International. Right now, governments are too afraid to respond properly to scandals.
The state should do nothing to enhance the self-importance of church officials. Let them strut around in scarlet - we may all dress as we choose - but never roll out the red carpet for them. When a much-abused Republic of Ireland was struggling to bring the Vatican to account, it was an absolute disgrace for the UK government to bring the Pope here and grovel to him. (The invitation came from Mr Blair and was renewed by Mr Brown).
Personal religious belief often sustains people in adversity and sometimes leads them to acts of personal heroism and sacrifice. It should be respected, not least because that belief is often enough abused and betrayed by the self-serving bureaucracies and hierarchies of religious organisations.
Believers deserve better than their churches, and they will only get it if the state keeps those churches in check.