NPR.

This is the indicator from Planet Money.

I'm Adrienne Ma.

And I'm Whalen Wong.

The Pentagon's decision to pull some American troops out of Germany

represents a fresh chill in the relationship

between the U.S. and its European allies in NATO.

The North Atlantic Treaty Organization is one of the pillars of the post-World War II global order.

And historian Heather Cox Richardson says it has yielded huge benefits for the U.S. and the rest of the world.

This is a defensive alliance that has this extraordinary payoff.

Look even at hand now at how much the United States of America is spending in Iran alone.

That's a billion dollars a day.

So if you think about this not as a tit for tat and you think of it more as a concept of how the world should operate, NATO is really cheap.

President Trump, however, does talk about NATO like it's a tit for tat.

He was once quoted as saying at a campaign rally, if they're not going to pay, we're not going to protect.

And that makes NATO sound more like a protection racket than a strategic alliance. So, is that what NATO is?

Today on the show, we examine Trump's view of NATO, how this long-standing alliance is becoming

strained, and how the U.S. could pay the cost both politically and economically

for those frayed relationships.

Historian Heather Cox Richardson writes a newsletter called Letters from an American.

It has around 3 million subscribers.

Her focus is explaining how we got to our current moment.

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