IT WAS a single remark in an interview with the New York Times, but it rattled the strongest military alliance the world has ever seen. On July 20th Donald Trump declared that should the Baltic states be attacked by Russia when he is president, he would come to their aid only if he felt they had met their “obligations”. That would contravene Article 5, the bedrock of NATO’s founding treaty, which holds that an attack on one member is an attack on all. NATO’s secretary-general, Jens Stoltenberg, soon pushed back: although he did not wish to interfere in an American election, he said, “solidarity among allies is a key value for NATO.”
