Highest Office Held: President of the United States
Poverty can drive a man to do some wild things. Madison left the presidency far poorer than when he had arrived, after plummeting tobacco prices and an inept stepson pushed his plantation into financial ruin.
With few assets left, Madison became obsessed with the value of his personal letters, which he hoped would sustain his wife Dolly after his death. He spent wild amounts of time rewriting, expanding, and altering his letters, vainly hoping that he could somehow increase their value. There's even proof that he changed Thomas Jefferson's handwriting in some of their correspondence.
All this letter-altering served him about as well as you'd think it would. Dolly Madison was forced to sell Montpelier Mansion and the surrounding lands just to survive after Madison's death.