The United States currently has an opt- in system for organ donations from the deceased: People must explicitly choose postmortem donation ahead of time (as when they obtain their driver's licenses). Many nations have "out-out" systems: A desire to donate post mortem is presumed to exist unless the individual explicitly chooses ahead of time not to permit donation. How-if at all- would a shift to an opt- out system likely change the supply of cadaveric (postmortem) donations?