Armchair lawyers often throw around caution about the color of ink that is needed when signing a legal document, and they certainly do not approve of using a pencil. If there was ever any doubt about the legality of pencil-written missives, consider the outcome of one such document.
On July 31, 1945 President Harry S. Truman was in Potsdam, Germany for his meeting with the leaders of the Allies. He received an urgent top-secret cable from the War Department, advising him that preparations for use of the atomic bomb were complete, and the President’s final approval was needed for its scheduled use.
President Truman considered the communique. Making his decision, he flipped the pink paper over, and on its back he wrote these words — in pencil:
Reply to your 41011 suggestions approved. Release when ready but not sooner than
No one has challenged the legality of this use of the Presidential pencil.