I WAS recently a guest speaker at the Cove and Kilcreggan Book Festival. During my session, a member of the audience asked me a question that, for a writer on foreign affairs, is a now-familiar one. Is the United Nations fit for purpose, the questioner enquired?

As ever in responding, I pointed out how much I shared the questioner’s scepticism about the role of the UN, and concern over its failings and inadequacies, but added that while the international body is often criticised, few among us seem able to come up with a viable alternative to replace it.

I couldn’t help thinking much the same this week as the wrangle over Nato’s role and function intensified when the organisation’s leaders gathered in Watford for a 70th-anniversary summit.

What should have been a birthday celebration instead had all the traits of a tense Christmas dinner for a large dysfunctional family. Amid all the niggling and snide remarks, there was, in the end, that sense of reluctant resignation from everyone around the table that they were stuck with each other.

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The North Atlantic Treaty Organisation (Nato) was founded in the uncertain days of 1949 after the Soviet Union had consolidated its control of “eastern Europe”.

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It was the British soldier General Hastings Lionel Ismay – Churchill’s wartime chief of staff – who rather tellingly described Nato’s aims as “to keep the Russians out, the Americans in, and the Germans down”.

In the intervening years since then, the alliance has often been described as the most successful in history, but this is to belie some fairly traumatic moments of division among its members – not least the decision back in 1966 by then French president Charles de Gaulle to remove French forces from Nato’s integrated military structures and to remove Nato’s headquarters and forces from France.

Today, once again it has been another French leader, President Emmanuel Macron, who has been cast in the role of agent provocateur within Nato’s dysfunctional family, after having the temerity recently to describe the organisation as “strategically brain dead”.

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Macron, of course, had made his criticism partly to reflect his frustration that Turkey, a Nato member, had entered northern Syria in October without co-ordination with any Nato partner apart from US President Donald Trump.

Macron’s reading of the situation stems from his belief that the Turkish invasion has undermined the fight against Islamic State group, or Daesh, not to mention betraying the Kurds, our loyal allies in that fight.

I’m probably not alone in concurring with the French president’s views on this contentious issue, given that the neat little agreement between Washington and Ankara does seem to make something of a mockery of Nato’s solidarity as an alliance. But do such tensions within the organisation really point to signs that it’s not fit for purpose?

It is the famous Article 5 that acts as the fundamental principle underpinning this US-Europe military alliance, stating that if any member of Nato is attacked, then all of Nato will rush to defend that country.

Watching the bickering in Watford this week, it would be all too easy to dismiss the notion that Article 5 still matters as little more than fanciful. After all, Nato only works as long as all 29 member countries remain continuously on board with the promise that they will fight even if the war doesn’t directly involve them.

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This week’s anniversary summit might have looked like an unruly gathering, but perhaps there was not as much damage done as appeared and as some had predicted.

This limitation matters because Nato matters, even if membership has often been a bone of contention in many quarters – including here in Scotland.

We need only cast our minds back to past SNP conferences and questions over Trident and Nato to realise how much of a controversial and potentially divisive issue this can be. Back in 2014 during the independence referendum, the question of Nato membership was also up for serious discussion should Scotland have voted a resounding Yes.

Most experts believed back then, and still do, that Scotland would be accepted into the Nato alliance should that be its chosen direction of travel. Not everyone, of course, might want this and certainly the security landscape has evolved since then, with countries like France and Germany drawing up plans in increasing the EU’s security independence from Nato.

Other countries do it differently, too, like Sweden or the Republic of Ireland, who remain neutral while providing peacekeeping forces under the auspices of the UN.

If a survey conducted to coincide with the Nato leaders’ meeting this week is anything to go by, it would appear that the UK public by and large still thinks Nato matters.

The survey conducted by YouGov-Cambridge Centre in conjunction with the Royal United Services Institute (RUSI) found that some four-fifths of the country (79%) still think membership of Nato is important to maintaining UK national interests.

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Looking around a troubled world today it’s hard to disagree with that. Thinking back to 2014 to what some regard as a watershed moment for Nato only reinforces that view. For it was then that Russia annexed the Crimean Peninsula and at the same time the then leader of Daesh, Abu Bakr al-Baghdadi, declared a global caliphate when the terror group took the Iraqi city of Mosul.

Both events were sharp reminders of how instability can rapidly grip a region and pose enormous threats to global security. Tackling such threats requires both massive resources and transnational co-operation that Nato, with all its problems and flaws, is still capable of delivering.

Rancourous as this week’s alliance meeting was, it was still able to set out a declaration focusing on new technological and cyber threats, while for the first time mentioning China as a challenge.

I tend to be with German Chancellor Angela Merkel on this one, who recently pointed out in the Bundestag that better developed EU defence structures should complement, not replace, Nato.

Merkel is right in saying that for the time being Europe can’t defend itself on its own and, like it or not, we are reliant on the transatlantic alliance. Unpalatable as this might be, it shows a sharp sense of realpolitik.

Like the UN, Nato has many failings and some will continue to argue that it’s not fit for purpose. But for now, it’s what we have and until there’s a viable and credible alternative it would be foolhardy to suggest otherwise.