At a closed meeting of NATO leaders in Brussels in July 2018, US President Donald Trump shocked allies by threatening to withdraw the United States from the alliance, which could have led to the collapse of the military bloc. Former NATO Secretary General Jens Stoltenberg recounted this in his book, "On My Watch: Leading NATO in Wartime," excerpts of which were published by The Guardian. According to Stoltenberg, this tense moment marked a turning point for the organization, which had existed for 70 years at the time.

During the summit, Trump sharply criticized his alliance partners for their reliance on US military power and insufficient defense spending. He insisted that member countries increase their military budgets to a level consistent with NATO's 2% of GDP commitment.

"Look, if we leave, we leave. You desperately need NATO. We don't need NATO. Why should I keep paying for this organization when I don't need it?" — Stoltenberg quotes the American leader as saying.

Trump emphasized that the United States, by allocating about 4% of its GDP to defense, covers 80-90% of the alliance's expenses, which he considered an unfair burden on American taxpayers.

The climax came with Trump's announcement that he intended to leave the summit because he "sees no reason to stay." This raised concerns in Stoltenberg that the alliance might not survive such a crisis.

"This could be the meeting where NATO will fall apart," I thought. "And it's happening before my eyes. The Alliance managed to function successfully for 70 years, but not after July 12, 2018.", he recalled.

According to the former secretary general, the situation was so tense that some leaders began discussing emergency measures to maintain the unity of the bloc.