No fan of Montenegro. Photo: Mark Wilson/Getty Images

President Trump on Tuesday questioned the U.S. commitment to the mutual defense agreement between NATO nations in an interview with Fox News’ Tucker Carlson. The host raised the issue and proposed a hypothetical: “Let’s say Montenegro, which joined last year, is attacked.”

“Why should my son go to Montenegro to defend it against attack?” Carlson asked.

“I understand what you’re saying,” Trump said. “I’ve asked the same question.”

Trump says he's bothered by provisions of NATO that require the US to come to the defense of other member countries. pic.twitter.com/2xY1FjBTSn — Aaron Rupar (@atrupar) July 18, 2018

He went on to suggest that defending Montenegro, which has a population slightly smaller than Oklahoma City, could lead to World War III. “You know, Montenegro is a tiny country with very strong people,” he said. “They are very aggressive people, they may get aggressive, and congratulations, you’re in World War III. But that’s the way it was set up.”

Not everyone wanted Montenegro, NATO’s newest member, to join the alliance. A 2016 coup attempt aimed to kill Montenegro’s prime minister and put an alleged pro-Kremlin party in power. It failed and Montenegro was admitted to NATO in April of 2017.

Article 5, NATO’s mutual defense treaty, has been invoked only once, following the attacks on the U.S. on 9/11. There are still 39 NATO countries with troops in Afghanistan, Montenegro included.