It is the biggest test any politician faces. Ten past eight on BBC Radio 4, with a well-briefed John Humphrys huffing and puffing on the other side of the studio. The best of them just about manage to survive when grappling this ultimate challenge. Others crumple.
And then, in a category all on his own, stands the Archbishop of Canterbury.
Justin Welby is new to this game. He was elected to lead the Church of England's holy ministrations at the start of this year. He was succeeding Rowan Williams - a formidable veteran of rubbing the establishment up the wrong way, and an individual as learned as he was bearded.
Welby was different. He had a background in the City and in oil. He was one of the Church's self-confessed "thicker bishops". And he was chosen to lead the world's 77 million Anglicans.
When Welby went up against Humphrys this morning, he showed exactly why the Church made the right decision in backing him for the job.
This was a tough brief. His impulse to have a go at beating the payday lenders at their own game meant the Church was effectively beginning to dabble in usury. After it emerged the Church has actually invested tens of thousands of pounds in Wonga, the market leader he declared war on earlier this week, he had a lot of explaining to do.
So it is all the more remarkable that he emerged from the interview with his reputation not just unscathed but actually smelling of roses, as these tweets show:
Justin Welby doing an astonishingly good job of handling Humphrys on the Today programme. What an excellent man he sounds— Alexander Armstrong (@XanderArmstrong) July 26, 2013
Justin Welby pioneers new approach to kicking off the interview on Today Prog: Humphrys: 'Are you embarrassed?' Welby: 'Yes.' Humphrys 'er..— Glynn Harrison (@Glynnharry) July 26, 2013
Justin Welby came across very well on the Today programme. At last CofE have found someone who Thinks and can communicate. Well Done!— Neil Wright (@wrightnj7) July 26, 2013
Congratulations to Justin Welby @ABCJustin on BBC R4 Today exploring openly how we follow Jesus in a sinful world, yet still make mistakes.— Derrick Hill (@HillDerwent) July 26, 2013
How did he do it? Here's a quick analysis of the Welby technique, broken down into five gambits you'll rarely see a politician use:
1 - Answering the question
Any politician worth their salt knows this is a terrible idea. After beginning by admitting he was embarrassed, Humphrys asked Welby how much he was embarrassed, on a one-to-ten scale. Every minister knows the only correct response to this is to run to the hills. "About eight," Welby replied.
That's that settled then. Eighty per cent embarrassed. Humphrys appeared so surprised by this - what's he going to do with the number, after all? - he quickly moved on.
2 - Stating the painfully obvious
The political equivalent would be something like 'I think my party is the best'. Or 'the members opposite are not especially nice people'. What Welby came up with, when invited to clarify his position on sin, was the following:
Sin is a bad thing by definition. Just for the record, I'm not in favour of sin.
This had listeners up and down the country squealing with delight. It is not especially dignified to have to state the bleedin' obvious, because it suggests your underlying position is so ridiculous as to justify the question. Not that this bothered Welby, who got away with it because of the twinkle in his eye as he said it. Notwithstanding this, it was a moment to savour.
3 - Openly wishing you had more power
Everyone in a position of influence in Britain would always like to have a little bit more. They do not usually admit it. But Welby found himself doing just that as he explained the limited nature of his influence with the church commissioners.
"We're not the curia," he declared (let's hope they don't listen to the Today programme in the Vatican). "Nor do I have a suitable bunch of hard people who can beat up the church commissioners until they do what I want," he said. The vision of Roman Catholic officials biffing their way through the opposition is not one usually associated with an organisation that has been told, in no uncertain terms, that the meek will inherit the earth. Humphrys was as baffled as the rest of us, suggesting that Welby, as the archbishop, could do what he wants.
"You'd be very surprised," Welby replied. "I wish!"
4 - Admitting discomfort
Politicians are experts at brushing past the detail of a question - especially if something they'd said before is mentioned to them. Humphrys, talking about Welby's desire to "make us ethical, but only up to a point", was asking a simple question which any half-decent minister would have brushed over. As it was, he paused. And then admitted: "I was wondering when that quote would come up. You were a bit delayed, I was hoping for it a couple of minutes earlier and I've now forgotten the answer I had for it." This sort of honesty about the process is utterly refreshing.
5 - Admitting mistakes
It takes a lot for any minister to accept a genuine mistake. Doing so, in the partisan environment of British politics, will inevitably lead to mockery in the Commons bearpit and a permanent stain on your reputation. Welby, who leads a Church interested in forgiving where possible, is more balanced.
"We get it wrong plenty often, we're fallible as everyone else," he declared.
"We're trying to put our money where our mouth is and rather than stand on the sidelines and say 'you've got to do better', [we're going to] actually try and do something better ourselves as part of our witness to Jesus Christ and his love and the way we live in these communities."
Who? Jesus Christ? It was nine minutes into the interview before the Archbishop of Canterbury name-checked his main man.
Be warned, Archbishop. Your frankness and self-deprecation work up to a point. They are endearing because of their novelty. The risk, his communications advisers will be warning him, is that too much of this will start to make it look like the Church is losing its dignity.
There's a sense that Welby isn't particularly bothered. But his irritation "for a few minutes" suggests he is not impervious to frustration. This, he understands, is what happens when you don't live in heaven.
"We can't say we tolerate bad things but we've got to live in the real world," he said.
"And living in the real world means life is often very complicated."
Welby has the knack of explaining why we should accept the need for pragmatism, instead of striving for idealism. It's an attribute all politicians would do well to aspire to.