After a long and protracted process which began with the Scott Rennie case in 2009, the Church of Scotland approved the solemnisation of same-sex marriages in the Church by a vote of 276 to 136 at this week's General Assembly in Edinburgh. Ministers can now apply to be celebrants, and no one will be compelled to take part.

The Moderator, Rev Dr Ian Greenshields, explained why this had taken so long.

"The Church of Scotland is a broad church and there are diverse views on the subject of same-sex marriage among its members.

"There has been a lengthy, prayerful and in-depth discussion and debate about this topic for many years at all levels of the Church to find a solution that respects diversity and values the beliefs of all."

There was considerable concern at the beginning of this process that the evangelicals would leave. Given the decline in the Church, the Church leaders were well aware of the devastating impact this would have – so they played the long game using a mix of carrot and stick.

On the one hand they appointed evangelical moderators (whose job was to ensure that the evangelicals stayed on board and ensured that there were theological commissions with evangelicals on board - although always a minority). On the other hand, they made it difficult for evangelicals to leave – for example playing hard ball over buildings and finances.

These tactics worked. Although a number of evangelicals did leave – including almost all the big evangelical congregations in the cities – there was not a mass exodus. Indeed, some evangelicals facilitated the change.

What does it mean?

The politicians approve. For example, the SNP tweeted their delight: "Congratulations to the Church of Scotland - to all those campaigners for today's historic moment! An overwhelming majority in the General Assembly in favour of allowing ministers to conduct same-sex marriages."

And of course, the media are on board. It is incomprehensible to most modern journalists how anyone could be opposed to same-sex marriage. To them it is like being opposed to love! The trouble is when you ask them to define 'love', they struggle.

The Church of Scotland is now fully on board with the progressive 'values' that run contemporary Scotland. This week they also passed a motion supporting the government's ban on so called 'conversion therapy'. It's strange that they appear to be silent about the other great social issue currently dividing society – transgender ideology. It would be good if the Assembly told us what a woman is and acted in defence of women.

Where is the Church going?

The answer is: to extinction. The Church of Scotland has seen a fall of a third of its membership in the past decade. The Trustees report stated: "A 34 per cent reduction was seen between 2011 and 2021, with no indication of this trend reversing from 2021 congregational data." Over the past 60 years, the Church has lost a million of the 1.3 million members it once enjoyed.

A BBC Scotland journalist suggested that the reason for this decline was because it had not accepted same-sex marriage sooner. The trouble with this description is that it is demonstrably false. Churches which are more liberal tend to decline more quickly. The work of John Hayward on Church growth modelling is fascinating and even The Times has taken note.

He argues from the data that the Church of Scotland is likely to be extinct by the middle of this century. He also shows that every church that has supported progressive ideology and same-sex marriage has declined.

There are some in the Church of Scotland who know this. Rev Phil Gunn, minister of Rosskeen Parish Church in Ross-shire, asked the Assembly: "A Church that does not provoke any crisis, preach a Gospel that does not unsettle, proclaim a Word of God that does not get under anyone's skin or a Word of God that does not touch the real sin of the society in which it is being proclaimed, what kind of Gospel is that?"

Unless the Church of Scotland returns to the Gospel, it will die. To some, this seems a strange statement. What does same-sex marriage have to do with the Gospel? It's straightforward. We do not make up the Gospel. We receive it by revelation from Christ – through his word. Part of that is his teaching about marriage. When we start to dismantle that word and rearrange it according to the views of our culture, then it is not the Gospel we believe, but ourselves. When we move away from Scripture, we move away from Christ. Whenever a Church does that, it withers and dies.

When the world lauds the Church for adopting its values, it is a sign that the Church is unnecessary, irrelevant and judged by Christ. That is why observing the General Assembly this week was a bit like being at a funeral. The stench of decline and spiritual death was everywhere.

Hayward expresses it well:

"I suspect many people in the church do not support the church's redefinition of marriage. But they do not have the power to prevent change.

"Like other older denominations, the Church of Scotland has a disconnect between its ecclesiastical leaders and its members. The former are not overly bothered by church decline. For them, the church is about politics and power, not size and conversion. The people who disagree are faced with the choice between leaving or staying in a congregation dominated by tensions between people for and against SSM.

"This is not a recipe for recovery but for accelerated decline. The future of the progressive denominations is bleak. Despite the enthusiasm of leaders for the new ideology, they face division and despondency in the church and a faster decline. The embrace of same-sex marriage is the final gasp of churches near the end of their lifecycle. Desperately sad."

Indeed.

David Robertson runs The ASK Project in Sydney, Australia. He blogs at the Wee Flea.