This story was originally published in the December 3 edition of CNN's Meanwhile in America, the daily email about US politics for global readers. Sign up here to receive it every weekday morning.

(CNN) NATO is having an unhappy birthday.

Champagne corks ought to be popping as leaders of the world's most powerful military alliance meet outside London this week. Founded in 1949 by countries mustering for a fight against Soviet communism, NATO won that victory 30 years ago, when the fall of the Berlin Wall heralded the collapse of the CCCP . It should have all been gravy from there.

But divisions and controversy are now tearing at NATO unity. Turkey is closer than ever to Russia -- the nation that the mutual defense alliance was first set up to counter. French President Emmanuel Macron has declared the "brain death" of the alliance, and German Chancellor Angela Merkel — an East German child of the Cold War — responded by giving him a rhetorical clip round the ear.

Normally, the US President might bang heads together. But Donald Trump himself is the most powerful destabilizing force facing NATO today.

It's not just that he berates allies for falling short of defense spending commitments (a fair criticism in many cases), or that he dismisses the threat that many NATO partners still perceive from the Kremlin. It's that Trump sees the historic alliance as a protection racket rather than a multiplier of US global diplomatic and military power. No one knows if he believes in NATO's bedrock principle of mutual self-defense.

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