Of all the warnings in President Trump's arsenal, quitting the NATO military alliance is among those he's wielded the most. Now he's doing it again.

Asked by Britain's Telegraph newspaper if he is reconsidering US membership of NATO, he said: Oh yes… I would say [it's] beyond reconsideration – fuming again that his partners weren't joining America's military operations, alongside Israel, against Iran.

I just think it should be automatic, he emphasized in his remarks to the paper. Trump's invective underlines again his misunderstanding of how this 32-member alliance works.

NATO's Article 5 does commit it to collective defense. An attack against one member is deemed to be an attack against all, but invoking this principle requires a consensus. And the 1949 treaty only referred to crises in Europe and North America.

One ally after another has held back from joining a war they weren't consulted on, given they still don't understand its goals in the face of mixed messaging from the Trump administration. Article 5 has only been triggered once, in the wake of the September 11th attacks on the US in 2001.

Trump also referenced Ukraine in the Telegraph, saying: We've been there automatically, including Ukraine. After Russia's full-scale invasion of Ukraine in February 2022, then-US President Joe Biden took a leading role in shaping the response of individual Western governments because he believed President Putin's actions threatened them all. NATO, as an alliance, provided assistance but avoided the dangerous prospect of becoming directly involved as a party to this conflict.

Even before Trump entered the White House in 2017, he repeatedly dismissed NATO as a paper tiger, described it as obsolete, and said it was costing a fortune for the US. This year, he has mocked the alliance, saying Russia would have occupied all of Ukraine if the US had not been NATO's enforcer.

Trump almost walked out in early 2019 during his first term. According to former NATO Secretary General Jens Stoltenberg, there were clear signs Trump was preparing to act on his threat. Stoltenberg noted in his memoir how he credited Trump with pressuring NATO allies to increase their military spending. Military spending has ramped up significantly by almost all NATO members, partly in response to Trump's threats, partly because of Russia's growing menace.

But the reality remains: the might of the US military matters immensely, as it now comprises about 62% of NATO's total defense spending and possesses unparalleled assets and intelligence capabilities.

Following Trump's recent comments, his Secretary of State Marco Rubio expressed skepticism about NATO's future. The US Congress has since voted to prohibit the president from unilaterally withdrawing from NATO without the approval of a two-thirds Senate majority or an act of Congress.

As NATO leaders prepare for discussions in Washington next week, they will aim to reinforce the importance of transatlantic unity and collective security amidst increasing global threats.