Over the course of the last couple of centuries, the Church of England has frequently if rather inaccurately been caricatured as "the Conservative Party at prayer."
If it was ever true, it certainly ceased to be so in the 1980s, when the church's trenchant critique of Margaret Thatcher's policies led to it being dubbed "Marxist" by Norman Tebbit – although perhaps the "SDP at prayer" would have been nearer the mark.
Thirty years on, the church again finds itself again in conflict with a Conservative-led administration, and for much the same sorts of reasons.
Just as Archbishop Robert Runcie in the 1980s took the Iron Lady to task over her government's apparent lack of concern for the poor and for social cohesion, so his present-day successor Rowan Williams is motivated chiefly by the impact of the government's reforms on the worst-off.
It would be tempting to think he had planned his attack to cause maximum discomfort for David Cameron in a week which has seen the Prime Minister forced to defend his handling of health and justice reforms.
Not so. The New Statesman article in which Dr Williams launched his salvo had been long planned, as the archbishop was actually guest-editing the publication.
In one sense, Dr Williams was simply doing his job. What on earth is a national church for, if not to occasionally offer a faith-based perspective on the politics of the day?
But of course his is not the only interpretation of how Christian teaching should impact on present-day political debates, as Roman Catholic archbishop Vincent Nichols reminded us when he praised the "genuine moral agenda" driving the Coalition's reforms.
Dr Williams' intervention may even have helped Mr Cameron this week by diverting attention from his internal difficulties over health and sentencing.
A fortnight ago, in this column, I posed the question whether the government's health reforms, and the career of health secretary Andrew Lansley, were now effectively dead in the water.
The answer on both counts would appear to be yes, with even the Health and Social Care Bill's central proposal for GP consortia to commission local health care now in danger of being watered-down.
And Justice Secretary Ken Clarke was forced to tear up his plan to give sentencing discounts to rapists and other offenders in return for early guilty pleas as Mr Cameron made a belated move in the direction of Prime Ministerial government.
Ordinarily this would all have presented a gift-horse to Labour, but the party is beset by internal difficulties of its own.
Party leader Ed Miliband was generally held to have had the worst of this week's Commons exchanges with Mr Cameron and the muttering over his leadership is increasing in volume.
The revelations about Shadow Chancellor Ed Balls' involvement in a "plot" to oust Tony Blair from power in 2005 will hardly help matters.
Having read some of the leaked documents myself yesterday, I would say a more accurate description of what was going on was a bid to rebrand Gordon Brown rather than oust Mr Blair, but the damage has been done.
Ultimately it is not up to archbishops to assemble a coherent critique of government policies. It is the opposition's job to do that.
And until Mr Miliband and Co can step up to the mark in that regard, Mr Cameron can continue to sleep easily in his bed at night.
That said, Dr Williams' claim that radical policies are being introduced "for which no–one voted" is a very hard one to answer – even if those self-same policies are now being trimmed.
The question of legitimacy that has dogged this Coalition from the start is not, I suspect, one that is going to go away in a hurry.