WASHINGTON—President Joe Biden marked his first Christmas in office by making calls to military service members stationed around the world, offering them holiday wishes and gratitude for their service and sacrifice for the nation. Joined by his wife, Jill, and their new puppy, Commander, the president on Saturday spoke via video to service members representing the Army, Marine Corps., Navy, Air Force, Space Force, and Coast Guard, stationed at bases in Qatar, Romania, Bahrain, and the United States. “As your commander in chief, I wanted to take this opportunity to say thank you, thank you, thank you,” he told the service members. “We’re grateful for your courage, your sacrifice, not only your sacrifice but your family’s sacrifice.” Speaking from a studio set up at the White House, Biden told them they’re “the solid steel spine of the nation,” and emphasized the “truly sacred obligation” the nation has to care for …