Not unexpectedly, President Recep Tayyip Erdogan of Turkey has thrown a spanner in the works at a critical juncture in international relations. He has effected a setback to the expansion of the North Atlantic Treaty Organisation. Giventhat Sweden and Finland are the new applicants for membership, he has iterated his trenchant criticism of the government in Stockholm, as it nurtures what he calls a haven for Kurdish separatists, raising fresh questions about what will satisfy him sufficiently to back Nato membership for the two countries.

The Turkish President had said last week that his country would “not view positively” the applications of the two countries for membership of the alliance. He confined his criticism to Sweden, which has been welcoming Kurdish refugees. Both Sweden and Finland have let it be known that they would apply to join Nato. Both countries are aware of Ankara’s reservations and have resolved to send senior diplomats to Turkey to discuss the objections of the Erdogan government. The Turkish President appears to have firmed up his decision. “Are they coming to convince us?

Excuse me, but they should not tire themselves,” was his decidedly blunt message to the governments in Stockholm and Helsinki. Both countries, he said, are yet to evolve a firm stand against terrorism; quite simply, they refuse to extradite terrorists.

It is hard not to wonder whether the 21st century Concert of Europe is faltering. Turkey has reportedly asked Finland and Sweden to return 33 people with alleged links to two groups which it deems to be terrorist organizations. Both countries have refused. There appears to be a rather strange connecting strand between Russia and Finland. This is clear from President Erdogan’s perception ~ “If Finland and Sweden join Nato, then it becomes a place where representatives of terrorists are concentrated.” Sweden and Finland will be discomfited if they are blackballed, but the impact will be far greater in Washington which seems determined to put Russia in its place.

President Biden met leaders of Sweden and Finland at the White House on Thursday to offer robust US support for their applications to join Nato. “Finland and Sweden make Nato stronger,” Mr Biden said. “They are strong, strong democracies, and a strong united Nato is the foundation of America’s security. Having two new Nato members in the high north will enhance the security of our alliance and deepen our security cooperation across the board.”

All 30 Nato members need to approve any new entrant. Turkey, which has tried hard to broker peace between Russia and Ukraine, has told allies that it will reject the membership of Sweden and Finland. The unstated reason could well be that any effort towards peace will be effectively stymied by Nato’s expansion, especially as Russia’s reason for the war is the threat it sees on its doorstep. On test is the finesse of President Biden’s diplomacy and the ability of President Erdogan to stand firm.