When politicians grab and wave the chalice of religion, they tarnish its beauty and purpose, turning its gold to nickel.
Let me put it another way: they sully and invade the privacy of faith and misuse God for propaganda and political games.
The master of this dark art was the Ayatollah Khomeini, who swept into power in Iran in 1979. His political takeover was disguised as religious salvation. We know what happened next.
Saudi Arabia is the most loathsome, extreme theocratic state. In India, the Hindu fundamentalist BJP party has successfully sold itself to countless supporters and the apartheid regime in South Africa cited the Bible to justify its racism.
Just as common and corrosive is the everyday manipulation of religion by politicians. Recently, David Cameron did just that. He chose the season of peace and goodwill to rouse jingoism, partly to pick a fight again with 'multiculturalism', but mostly to cleanse the many sins of his government.
This is a Christian country, with Christian values, he decreed, and "we should not be afraid to say so". Only it isn't. When you consider our domestic and foreign policy, Britain cannot be called Christian.
I wish it was. For, at its best, Christianity is one of the world's most humane and tender of religions and deserves a better class of worshipper than many of those who lay claim to it.
There are, of course, people who do follow the example of their Lord; they are, though, diminishing. A 2010 survey found a long-term, steady decline in the number of practising Christians in Britain.
Fifty per cent said they followed no organised religion. In 1983, that figure was 19%. Among 18- to 24-year-olds, the numbers of disbelievers today is 64%.
These figures delight fundamentalist atheists like Richard Dawkins and the late Christopher Hitchens.
They are winning many devotees - but not from the pesky 6% of the population who are non-Christians.
Atheism is a foreign concept. Oh, we know well enough the evils carried out in the name of all the world's major religions and the wicked individuals who think worship gives them immunity from censure and judgment. However, faith helps to stave off fears when you are part of a minority and many of us feel it wakes our consciences and reminds us of those human faults: vanity, selfishness, righteousness, prejudices and greed.
If Britain were a more Christian country, its people would not tolerate the rich, ruling elite punishing the most disadvantaged with harsh laws and unfair rhetoric.
They would revolt against the state-created poverty upon us. They would preserve the welfare state - born at a time when the country was more Christian and understood the obligations of society. That is now gone.
Too many are like David Cameron, part-time Christians of convenience, living for mammon, who use their religion as a weapon against those they despise, the poor, helpless and 'alien': all those types and creeds embraced by Jesus Christ in his time.