Last week, the acting US secretary of defence Patrick Shanahan penned a polite and formal letter to his Turkish counterpart. Its content, however, was far from cordial. He wrote that if Turkey were to follow through with its purchase of the Russian S-400 missile defence system, then Turkey's participation in the F-35 joint strike fighter programme would be discontinued.
If that were not enough, the letter also warned that Turkey could face action under the Countering America’s Adversaries Through Sanctions Act, and that Turkey’s decisions would hinder the its own “ability to enhance or maintain co-operation with the United States and within Nato”.
This was the most harshly worded correspondence from the US to Turkey since 1964, when US President Lyndon B Johnson wrote to Ismet Inonu, warning the Turkish Prime Minister not to intervene in the Cyprus crisis and highlighting the damage such a move would cause to Nato.
Back in 1964, a shocked and disappointed Ankara reluctantly heeded Johnson's demands. This time, however, President Recep Tayyip Erdogan has rebuffed Washington and insisted that there is no going back on the S-400 deal. Instead, it was reported that upon their receipt, Turkey might position S-400 batteries towards the east Mediterranean, a posture threatening to Cyprus, given the dispute between the two nations over drilling for offshore natural gas. Ankara also intimated that if excluded from the F-35 programme, it might purchase Chinese J-31s or Russian Su-57s instead.
Turkey, a Nato member since 1952, has the second-largest army in the alliance. Located in an important geostrategic region, Nato benefits from the use of several Turkish bases and enjoys the nation’s support in the Aegean and Black Sea. Turkey has also participated in important Nato missions, such as those in Kosovo and Afghanistan.
But, from the US perspective, these contributions may no longer be enough. The S-400 issue is just one of a number of US misgivings. These include Mr Erdogan’s threat to “Ottoman slap” the US military in Syria, where positions of special forces had been leaked by Ankara; the arbitrary arrest and imprisonment of US citizens and consular workers; Turkey’s initial blind eye to foreign fighters crossing its border into Syria to join ISIS; not to mention Erdogan’s bodyguards attacking protesters carrying the flag of a Kurdish political party outside Turkish ambassador’s residence in Washington DC, two years ago. If that was not enough, last year a Turkish state-owned bank was found to be in violation of the Iran Sanctions Act, and Ankara has openly sided with US enemies, most recently President Nicolas Maduro in Venezuela.
Following these developments, it is little wonder that some commentators have argued that Turkey should be expelled from Nato. However, doing so would be very difficult.
There is nothing written in the North Atlantic Treaty that pertains to expulsion. Nor is there a precedent for removing a member state. A country may leave Nato of its own volition. Article 13 states that “any Party may cease to be a Party one year after its notice of denunciation”.
However, if Nato members were absolutely determined to expel Turkey, such an action would have to pass through the North Atlantic Council (NAC), the organisation’s senior decision-making body.
However, NAC decisions must be agreed unanimously by all 29 member states. In the unlikely event that all of Nato’s members concur that Turkey should be ousted, all Ankara has to do is use its veto.
But there is no reason to suspect that Turkey wants to leave. Nato offers it a strategic umbrella, a fallback alliance, in case it finds itself in trouble with belligerent neighbours such as Iran and Russia. Turkey’s membership is central to Ankara’s security relations with the EU, and Nato offers Turkey information and intelligence exchanges, as well as the opportunity to participate in joint military exercises and training.
The only conceivable scenario where Turkey’s veto would be ignored is in the very unlikely event of a direct and deliberate Turkish strike against another Nato member state. This might trigger Article 5, which states that “an armed attack against one or more… shall be considered an attack against them all”. This is highly improbable.
In short, Turkey cannot and will not be formally expelled from Nato. However, upon its receipt of the S-400s, it will no doubt find itself increasingly isolated inside Nato's civilian and military bodies. To some extent, this has already happened. Last month it was reported that Turkish military and civilian personnel were not invited to important meetings about air defence and intelligence. In future, such exclusions will become more regular.
The US and other Nato members would slowly reduce their reliance on Turkish bases and increase their presence and infrastructure in other nations, such as Greece, Cyprus, Jordan, or, in a nightmare scenario for Turkey, Iraqi Kurdistan. Meanwhile, Turkey’s role in Nato operations will be also discouraged, and when Nato plans and prepares future strategies and tactics, Turkey’s interests will be ignored or sidelined.
If Turkey’s ties with the US, the most important member of Nato, continue in their current trajectory, it will find itself a member of Nato in name only – a disappointing end to a 67-year association.
Dr Simon A Waldman is an associate fellow at the Henry Jackson Society and visiting research fellow at King’s College London