As Nato’s leaders meet in London in muted celebration of the western alliance’s 70th anniversary, the treaty organisation faces deep internal divisions.
Over the past 10 years, Nato has been buffeted by fierce geopolitical headwinds.
When the alliance celebrated the close of its sixth decade it was yet to contend with the shifts sparked by the 2011 uprisings in the Middle East or Russia’s annexation of the Crimea and the Eastern Ukraine.
Ostensibly the leaders will meet to discuss Russia, Nato’s raison d'être, challenges posed by non-state actors in areas such as cyber space and, for the first time, the growing influence of China.
But ahead of the summit, Nato’s internal divisions have dominated. Since before he was elected, US President Donald Trump has questioned the necessity of Nato, the cornerstone of US foreign and defence policy in the 20th century.
The US withdrawal from northern Syria has exposed the fault lines at the heart of Nato even further.
French President Emmanuel Macron has publicly vented his frustration at not being consulted over the US withdrawal, criticising the Turkish offensive in northern Syria and calling the Nato alliance “brain-dead” over its handling of the crisis.
Turkey’s President, Recep Tayyip Erdogan, has fired back at the French leader, accusing him of supporting terrorism .
Former British ambassador Ian Bond told The National Mr Macron had caused problems within the alliance between Turkey and the US and provoked an "explosion" from Mr Erdogan.
He said the French leader was also making increasingly worrying overtures to Russia.
In reimagining a new foreign policy for Europe, Mr Macron has caused friction with Berlin and Washington, not least because of his calls for European “strategic autonomy” in defence and foreign policy.
But it is as the French president looks to rebuild relations with Moscow that Mr Bond has warned he may be making his greatest misstep.
“I think he is falling into a trap that a number of western statesmen have fallen into in the last 20 years of assuming that Putin can be persuaded to see the world in the same way we do if you just get the message right,” said Mr Bond, director of foreign policy at the Centre for European Reform.
“He hasn't thought as much as he might about how European security looks if you are in the Kremlin.”
There are real concerns that if in their statements the leaders start making accusations at the Nato summit, the signatories could leave London even more divided.
“With the UK domestic political environment in flux and a long list of challenges on the agenda, the Nato summit is likely to leave open more questions than it answers,” said Dr Lindsay Newman, senior research fellow at Chatham House.
“The question will be how the Trump administration balances its ‘America First’ foreign policy priorities with Nato and US public opinion with its future engagement with the alliance."
There had been hopes, when the summit was agreed to in May, that Britain would have left the EU by the time the summit came around.
The leaders’ meeting would have offered Britain the opportunity to reassert its commitment to European security outside the EU and possibly reprise its traditional role as a bridge between Washington and European capitals.
But with UK domestic politics still stuck in a quagmire, there is little chance Britain will be able to help smooth over the cracks as host nation.