BRUSSELS (AP) — Secretary-General Jens Stoltenberg, one of NATO's longest-serving leaders, officially stepped down on Tuesday. In his place, former Dutch Prime Minister Mark Rutte assumes the role, guiding the military alliance through some of the most formidable challenges it has ever faced. The two leaders, who first shared the NATO meeting table as representatives of Norway and the Netherlands 14 years ago, exchanged greetings in front of NATO’s headquarters in Brussels. Standing before