Okay kiddo, imagine you're playing a game with your friends on the playground. There's a rule that says everyone can have fun and play together, but if someone breaks the rule, they get punished.
Well, in the Soviet Union, Joseph Stalin was like the boss of the playground. He made a lot of rules, but some of them were pretty unfair. If someone didn't agree with him or did something he didn't like, he would punish them really harshly.
This punishment was called political repression, and it meant that people weren't allowed to say what they wanted or think for themselves. They could get thrown in jail or even killed for speaking out against the government. That's right, even just talking about what they believed could get them in trouble.
It wasn't just regular people who got punished. Sometimes, even other politicians or important leaders were targeted if they didn't agree with Stalin. The Soviet Union was supposed to be a country where everyone was equal, but political repression made it so that only certain people in power had a voice.
It was like playing a game on the playground, where the boss decided the rules and enforced them really strictly. But it wasn't fair, because some people were singled out and punished just for being themselves. That's why political repression was considered a really bad thing in the Soviet Union, and why it's important to value freedom of speech and expression.