As they prepared for this week's NATO summit ⁠in ⁠Ankara, the leaders of America's allies wondered which Donald ⁠Trump would join them - the friendly U.S. president who has praised the dedication of NATO allies or the testy Trump who has ​threatened to implode the 77-year-old alliance?

President Trump said the United States would license Ukraine to produce Patriots, which can intercept ballistic missiles.

The first belonged to President Trump, who dominated the news cycle with a steady stream of complaints, grievances and insults aimed at his NATO colleagues, with his unpredictable changes of tone and ...