NATO Secretary-General Mark Rutte is working to keep the alliance united and Donald Trump engaged. But disputes over burden sharing, US military commitments, and the Iran war are creating a major test for NATO unity.

In a Truth Social post on Thursday, Trump complained the United States was spending money to protect NATO members "without getting any benefit from so doing."

NATO Secretary-General Mark Rutte is working to keep the alliance united and Donald Trump engaged. But disputes over burden sharing, US military commitments, and the Iran war are…