Moreover, Trump devoted much of his Brussels speech, the highlight of his first presidential trip to NATO, to berating the allies for not paying their fair share. Nothing particularly wrong with that, or new — half a century ago Senate Majority Leader Mike Mansfield was so offended by NATO free riding that he called for major reductions of U.S. troops in Europe.

That’s an American perennial. But if you’re going to berate, at least reassure as well. Especially given rising Russian threats and aggression. Especially given that Trump’s speech was teed up precisely for such reassurance. An administration official had spread the word that he would use the speech to endorse Article 5. And it was delivered at a ceremony honoring the first and only invocation of Article 5 — ironically enough, by the allies in support of America after 9/11.

And yet Trump deliberately, defiantly refused to simply say it: America will always honor its commitment under Article 5 .