"Both camps maneuvered to win the endorsement of Kaiser Wilhelm, who, as the nation's supreme military leader, had the final say. He authorized U-boat commanders to sink any ship, regardless of flag or markings, if they had reason to believe it was British or French. More importantly, he gave the captains permission to do so while submerged, without warning. The most important effect of all this was to leave the determination as to which ships were to be spared, which to be sunk, to the discretion of individual U-boat commanders. Thus a lone submarine captain, typically a young man in his twenties or thirties, ambitious, driven to accumulate as much sunk tonnage as possible, far from his base and unable to make wireless contact with superiors, his vision limited to the small and distant view afforded by a periscope, now held the power to make a mistake that could change the outcome of the entire war. As Chancellor Bethmann would later put it, "Unhappily, it depends upon the attitude of a single submarine commander whether America will or will not declare war."