CONGRESSIONAL TESTIMONY by Donald Trump’s national security nominees last week suggested that the incoming administration would not seek to dismantle the alliances that have undergirded the West — and U.S. global leadership — since 1945. “If we did not have NATO today, we would need to create it,” said defense secretary nominee James N. Mattis. The U.S. treaty commitment to defend its European allies, said secretary of state nominee Rex Tillerson, is “inviolable.”

It is still not clear, however, that Mr. Trump agrees. In an interview published by the Times of London on Monday, he recalled his claim last year that NATO was “obsolete” because it did not fight terrorism (though it does) and because many of its members did not meet its defense spending guidelines….

As for NATO, Mr. Mattis was right to tell the Senate Armed Services Committee that it “is the most successful military alliance in modern world history.” It has greatly magnified U.S. power and global influence, even when its members were underspending on their military forces. Without it, the West would have no effective way to contain Russian neo-imperialism.

Ms. Merkel said she will wait to see what Mr. Trump does when he is in office. It’s probably naive to hope that he will modulate his rhetoric. But Americans who value their country’s place in the world, including Mr. Trump’s Cabinet members, should do their best to ensure that he does not act on it. Once destroyed, the West’s alliances will not be easily rebuilt.

Image: Donald Trump, James Mattis, and Mike Pence, Nov. 20, 2016 (photo: GIGA)