Squabbling and uncertainty cloud NATO’s focus

President Trump left NATO’s anniversary celebrations in London early and on the defensive after lashing out over a video that caught Canada’s prime minister and other world leaders apparently venting about him at a reception.

But the North Atlantic alliance faces more serious dilemmas than gossip and name calling, among them new technologies, new rivals, new weapons and a changing America, our correspondents write.

Mr. Trump’s withdrawal helped reinforce the fear that the alliance has lost focus, leaving NATO uncertain about whether its primary mission is defending against Russia, Iran, China or an array of new cyber and disinformation threats.

And then there’s Mr. Trump himself. “The single biggest challenge is absence of U.S. presidential leadership,” said Douglas Lute, the U.S. ambassador to NATO until 2017.