The US and Turkey – one of Washington’s key Nato allies – appear to be on a collision course this summer.
Turkey insists it will go ahead with the purchase of an advanced Russian S-400 air defence system. The first missiles and their associated radars could start to be delivered in July.
The US is urging Ankara to re-consider. It is warning that if the deal goes ahead then Turkey will be cut out of the F-35 warplane programme – the advanced US aircraft that will equip many Nato air forces over the coming decade.
So this is a controversy that has security, strategic and industrial dimensions. It raises questions about Turkey’s reliability as a Nato partner and the diplomatic course that it is pursuing. And given its key geographical location on the alliance’s southern flank – not to mention its role in the Syrian crisis – Turkey is not a country that Nato can turn its back on.
Washington’s concerns about Turkey’s purchase of the S-400 stem from both practical and security considerations.