system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why was double jeopardy introduced as a law in the US?

Edit: If anyone's still reading this. This question was indeed based off of the movie "double jeopardy".
gpt
Double jeopardy protects defendants by only allowing the state one shot at a case. Without it a prosecutor could retry the same case over and over. The state has basically unlimited time and money to do this, but it would ruin the defendant's life to be constantly in court. It also helps prevent prosecutors from presenting weak or frivolous cases. They know they only get one attempt, so they have to give it their best shot. This is why prosecutors and police are often willing to wait years to go to trial on a serious case. They want to make sure they have ALL the evidence.