The governor usually leaves office because their term ends and they have not been re-elected. But the governor may also leave office through other means. For example, the governor may resign from office. Four governors have resigned: William Barstow due to fraud allegations, Robert La Follette, Sr. to take his seat in the United States Senate, Patrick Joseph Lucey to become Ambassador to Mexico, and Tommy Thompson to become United States Secretary of Health and Human Services. Additionally two governors—Louis Harvey and Walter Samuel Goodland—died while in office, and Orland Loomis, who was elected governor, died before taking office.