On paper, the church and the state should have nothing to do with each other.

The constitution bans the federal government from having religious considerations or preferences and there is serious cultural hesitancy when it comes to politicians discussing their religious activity in public.

When Scott Morrison was quizzed about his religious life on Kitchen Cabinet this week, he had a typical MP reaction. That is: not keen to expand on the subject.

The cabinet minister shrugged off questions about his move from the Uniting Church as a child to the Pentecostal congregation Shirelive as an adult. And he would not be drawn on Annabel Crabb's inquiries about "happy clapping" and speaking in tongues (although he did note he didn't partake in glossolalia himself).

Morrison – a man used to dealing with difficult questions – was resolute that his relationship with God was his business. In fact, he appeared more comfortable talking about the 14-year IVF struggle he went through with his wife than Sundays at Shirelive.

Even Tony Abbott, who trained as a priest and never hid his Catholicism, has been careful to distinguish between the political and the religious.

"Faith has certainly helped shape my life, but it doesn't in any way determine my politics," he said just before the federal election in 2013.

"Faith is a splendid thing in private life, it can often be quite a misleading guide in public life."

But then again, it's not as though politics is hermetically sealed from religion. Christianity quietly pervades the way our political system operates.

The preamble to the constitution begins with a note about Australia's humble reliance "on the blessing of Almighty God". And every day Federal Parliament has sat since 1901 has begun with the recitation of the Lord's Prayer.

These things are fixtures.

Despite talk of updating the preamble, there is zero talk of changing it to get rid of a religious reference that doesn't apply to the 30 per cent of Australians that identified in the last census as either "non-Christian" or "no religion".

And multiple moves from Labor backbenchers and the Greens to scrap the Lord's Prayer (as an "anachronism" that doesn't reflect modern diversity) have been met with brick walls. As Eric Abetz – the guy who thinks the media should do more to call out the "godless left" in politics – opined, any move to get rid of the Lord's Prayer would "deny our heritage".

When they sign up to parliament – and if they're lucky, the ministry – MPs and senators have the option of swearing an oath (on a Bible or other religious book) or making a secular affirmation.

In a sign of the importance of religion to MPs, a clear majority swear the oath. In November 2013, 79 per cent of all members took the religious option, compared to 21 per cent for the secular. In the recent Turnbull gang trip to Government House, Marise Payne and Simon Birmingham were the only cabinet ministers to make an affirmation.

So religion is present and accounted for in parliament, even if we don't like really to talk about it and sort of pretend it's not here.

On Tuesday evening, Abbott took the church/state divide one step further, in extolling the virtues of Australia's religion-free approach to asylum seekers. Decked out in black tie for a dinner at London's medieval Guildhall, the former prime minister delivered a stern anti-immigration warning to his British hosts and their continental neighbours.

"The imperative to 'love your neighbour as yourself' is at the heart of every Western polity," he said.

"But right now this wholesome instinct is leading much of Europe into catastrophic error."

Spruiking Australia's "experience" with people smuggling, he said, "no country or continent can open its borders to all comers without fundamentally weakening itself".

In a similar mood on Kitchen Cabinet, Morrison talked about the need for a militaristic approach when he was immigration minister.

His job, he explained, was to be the people smugglers "worst nightmare".

"It was never about having a position on the victims of the crooks [the asylum seekers]."

In fact, the immigration gig wasn't even about immigration.

"The whole point about having stronger borders for me was about the integrity of the system, it's never been about immigration. It's never been about those issues at all," he said.

It's fair to say that debate about asylum seekers has been fraught for well over a decade now, spanning governments of many persuasions. There have been tragedies at sea and tragedies in detention centres, tears in parliament, angst in the community, protests, standoffs and a general air of unpleasantness.

According to the Coalition, we are now in calmer waters because, as they keep reminding us, boats no longer turn up in Australia. This fact seems to override or downplay any other concern that presents itself about the plight or treatment of asylum seekers and refugees.

You can argue the toss about how many lives have been saved by Operation Sovereign Borders, but how have we reached a point where avowedly Christian members of the Coalition are praising their approach to asylum seekers as a rejection of key Christian principles? And as one that explicitly isn't about the asylum seekers themselves?

The constitutional lawyers will hate it and the atheists might scream, but maybe it's time we stopped being so particular about this church vs state thing.

Maybe what politics needs now is more religion.

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