The North Atlantic Treaty Organization is facing a crisis.
The United States, Canada and 10 European nations formed NATO at the end of the Second World War to confront what they saw as threats from the Soviet Union.
Now, with 29 members, the biggest threats to the alliance appear to be internal.
The United States, Turkey and France have recently raised concerns about military spending and NATO's role in general, with the French president calling the organisation "brain dead".
What will happen if member states can't settle their differences?
Muhittin Ataman - Director of foreign policy studies at SETA, a political think-tank in Turkey
Marko Mihkelson - head of the Estonian delegation to the NATO parliamentary assembly
Kristine Berzina - Senior fellow, German Marshall Fund of the United States
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