SS Robin Moor; Wikimedia Commons

After allowing the passengers and crew to disembark to lifeboats, the German submarine U-69 sank the SS Robin Moor on May 21, 1941. The U-69 left some bread and butter for the survivors and explained that the ship had been sunk because she was carrying supplies to Germany’s enemy.

FDR’s response: 

“In brief, we must take the sinking of the Robin Moor as a warning to the United States not to resist the Nazi movement of world conquest. It is a warning that the United States may use the high seas of the world only with Nazi consent. Were we to yield on this we would inevitably submit to world domination at the hands of the present leaders of the German Reich. We are not yielding and we do not propose to yield.”—Franklin D. Roosevelt