Hamdan V. Rumsfeld is a court case that happened many years ago. It's about a man named Hamdan who was arrested and accused of doing things that were against the law. The person who arrested him was a man named Rumsfeld who worked for the government.
Hamdan didn't think he did anything wrong, so he went to court to try and prove his innocence. But when he got there, he found out that the rules were different than he thought. The government had made some new rules that said certain people who are accused of crimes can be put in jail without a trial or a chance to prove they are innocent. These rules are called "military commissions."
Hamdan and his lawyers didn't think this was fair. They said that everyone deserves a fair trial and a chance to prove they are innocent. They thought that the military commissions weren't legal because they didn't follow the rules of the court system.
The court agreed with Hamdan and his lawyers. They said that the military commissions weren't legal because they didn't follow the regular court rules. This means that everyone, even people who are accused of doing bad things, still have the right to a fair trial and a chance to prove they are innocent.