Why was Reagen a target in his assassination?

Often times, big public officials and celebrities become targets for assassinations. One reason is due to their popularity and the other main reason is due to the mental issue of those people. President Ronald Reagan was shot by John Hinckley Jr. He was returning from an engagement. Even though he was shot, he was not killed. He was just injured. Hinckley was also obsessed with Jodie Foster. Three others were shot when Reagan was shot.

The others that were shot included James Brady who was the White House Press Secretary at the time, Tim McCarthy who was a Secret Service agent and Thomas Delahanty who was a police officer. They all survived the gun shot but some of them were disabled as a result.