John Spencer, who played Leo McGarry, died from a heart attack on December 16, 2005 — about a year after his character experienced a nearly fatal heart attack on the show. A brief memorial message from Martin Sheen ran before "Running Mates", the first new episode that aired after Spencer's death. The loss of Spencer's character was addressed by the series beginning with the episode "Election Day", which aired on April 2, 2006.