Commentary By some estimates, 2,520 veterans of the D-Day operation, the largest amphibious invasion in history, remain alive in 2021. Less well known are the troops of the First Special Service Force (SSF)–an elite group of  Canadian and American fighters every bit as crucial to the victory over National Socialist (Nazi) Germany. The Canadians were drawn from regiments such as the Royal Winnipeg Rifles, while the American ranks included lumberjacks, miners, and former bodyguards for Hollywood stars. At Fort Harrison in Montana, they trained in parachuting, skiing, hand-to-hand combat, and mountain climbing—skills soon to be put into practice. After a campaign in the Aleutians, the SSF was off to Italy, where from Dec. 3 to 6, 1943, they engaged the Nazis at Monte la Difensa. The heavily laden SSF troops climbed the 3,120-foot peak through dense fog and snow. After this ordeal, easily the equivalent of a triathlon, the Canadians …