Throughout U.S. history, there have been countless plots and attempts to assassinate U.S. presidents. The first known case was a failed attempt on Andrew Jackson's life in 1835, where both the assassin's guns misfired due to moisture in the air, and Jackson then beat the culprit into submission with his cane. More recent attempts include separate, high-profile cases in October 2018, where sixteen bombs were sent via mail to prominent Democrats (including presidents Obama and Clinton), Trump critics, and news outlets; while another culprit sent letters laced with ricin to President Trump and senior U.S. military figures. Throughout history, the majority of these plots have been uncovered or prevented, however several have come close to achieving their aims, and four have resulted in the successful assassination of a sitting president.