system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why is testifying under oath still a thing when we all know that being under oath doesn't prevent people from lying to save themselves from being implicated in a crime?
gpt
It is called perjury (lying under oath), and is a crime. It is to prevent people from lying so someone they dislike goes to jail.

It is also why you have the 5th Amendment in the US Constitution, which gives you the right to not self incriminate.