Writing to his mother and sister back in Grandview, Mo., on April 12, 1945, Vice President Harry S. Truman passed along some exciting news: His coming radio address for Jefferson Day, which Franklin D. Roosevelt created to mark the third president’s birthday, would be broadcast nationwide the following evening.

It was a Thursday morning, and Truman was presiding over the Senate, listening to a “windy senator” make “a speech on a subject with which he is in no way familiar.” The senator’s verbosity provided a break in the action for the vice president, which gave him a few minutes to dash a quick note home. “Turn on your radio tomorrow night and you’ll hear Harry make a Jefferson Day address to the nation,” he wrote. “It will be followed by the president, whom I’ll introduce.”

Some 700 miles to the south, at his retreat in Warm Springs, Ga., President Roosevelt had put the finishing touches on his own Jefferson Day speech. He had been working on it all week, and at one point proudly announced to his guests that he had completed the draft largely in his own hand.

That morning, he sat for a portraitist, who diligently painted while Roosevelt chatted with his friends. Just as their table was being set for lunch, he complained of a sudden and piercing pain in his head. He slumped forward in his chair and never regained consciousness.