One of NATO’s guiding principles is collective defence, meaning “an attack on one is an attack on all”¹. So, by principle, NATO is defensive – it isn’t supposed to attack unless attacked or threatened itself.

There have been examples in the past of NATO members going to the brink of war with each other (Turkey-Greece). There has also been opposition from senior NATO members to military action proposed or undertaken by other NATO members.

NATO activated its collective defence clause under the terms of the treaty (“Article 5”) to support a US-led invasion of Afghanistan following the September 11^th attacks.

Nonetheless, NATO didn’t involve itself – as an alliance – in the US-UK-led Iraq War a few years later². The alliance only officially sanctioned deployments to protect the Turkish border.

The Iraq War was strongly opposed by several senior NATO members such as France, Germany and Belgium. However, other NATO members – such as Poland, Turkey and Spain – took part.

So, although there’s a principle of collective defence, NATO members still have some control over their own defence policies. NATO’s remit is also restricted to Europe and the Atlantic Ocean north of the Tropic of Cancer³.

As NATO makes its decisions by consensus rather than votes, Wales – as a full member – would be able to voice opposition if/when we decide to.

It could cause diplomatic and PR problems if Wales joined NATO to become a “naysayer”. In practical terms, however, NATO would only authorise military actions if there was unanimous agreement, or “Article 5” had been triggered.