Gee, I wonder where he heard this

In the 12 short years since Montenegro regained its independence, the European country has joined NATO, boosted its defense spending, and according to official figures contributes more troops per capita to the war in Afghanistan than the United States.

Yet this U.S. ally — smaller than Connecticut and about as populous as Baltimore — found itself in President Donald Trump's cross hairs late Tuesday as he once again criticized NATO.

Why NATO is criticized by Trump and opposed by Russia
The president suggested he would be unhappy defending "tiny" Montenegro if it were attacked, calling into question NATO's central principle of mutual defense.

He also questioned whether the country's "very aggressive people" could draw NATO into a war with Russia.

Like other presidents before him, Trump wants smaller NATO members to pull their weight by spending more on their militaries. But he's the first to directly challenge the alliance's mutual defense clause. Critics say that destabilizes one of the foundations of the post-World War II Western world.

Trump did not bring up Montenegro himself. It was used as an example by Tucker Carlson during an interview on Fox News.

"Membership in NATO obligates the members to defend any other member that's attacked," Carlson said. "So let’s say Montenegro, which joined last year, is attacked. Why should my son go to Montenegro to defend it from attack?"

Trump answered: "I understand what you're saying. I've asked the same question. Montenegro is a tiny country with very strong people … They're very aggressive people. They may get aggressive, and congratulations you're in World War III."

Fourteen people are currently on trial in Montenegro accused of plotting to kill the prime minister and stage a coup to bring a pro-Russian party to power. The government says one of the aims of the plan was to stop the country joining NATO. The Kremlin has denied any link to the alleged plot.

By saying that he had "asked the same question" why Americans troops should be asked to defend their allies, Trump was challenging the entire point of NATO.