The Sept. 10 incident in Poland was the first direct encounter between NATO and Moscow since the war in Ukraine began. It jolted leaders across Europe, raising questions about how prepared the alliance is against growing Russian aggression. Britain’s top diplomat has said the United Kingdom is ready to “confront” Russian planes if they enter NATO airspace. Foreign Secretary Yvette Cooper said Moscow’s “reckless actions risk a direct armed confrontation” between Russia and the Western military alliance. “We see a pattern: Russia is testing European borders, probing our resolve, undermining the security of the whole of Europe.