What is the best way to say 'the punishment should fit the crime? I'm sure a sage thought up a chengyu for it!

罪有应得

hi,

I think it means that the punishment should equal or proportionate the crime where minor crimes should be given light penalties, and heavy penalties for serious crimes.

although stealing $1 against $1,000,000 are both stealing, still, you can not grant a life imprisonment to the one who stole a buck, but rather a very light punishment or sometimes even settled at once.

I remember in the early 70's, in our country, when someone kills, he will be punished either by life imprisonment or death by electric chair.

sorry by the way, can't translate it in chinese.

:)

It is a question in make a decision whether the crime fit into the definition of law.

Argument: Some of these crimes weren't crimes in the past and some activities which used to be crimes are legal today. There was a time when you couldn't drink alcohol but you could legally smoke marijuana. In an even earlier era, you could own slaves but if you were a woman you couldn't own real estate.

'the punishment should fit the crime" interpreted as the crimes that fit into the definition of today's law.

Punishment is a tool with which to remove the cancer like growth of crime from society. When used properly, it forms barriers that are intended to prevent crimes from ever developing. But if used incorrectly, it can lead to injustices. Once this happens, the system can become just as bad if not worse than the criminals it attempts to protect society from. In most cases this does not happen because of safe guards and guidelines within the system. As it stands today, sentences are developed methodically by a process of reviewing individual characteristics of each criminal (ranging from their state of health, right through to their social environment) and then analysing the level of effect the crime had on society.

罚罪相当。罚，punishment; 罪， crime. 相当means equal. It is fit to your meaning , but I am not sure if it is a chengyu, The chengyu “咎由自取”or “罪有应得”， both means that a man is deserved for his crime, but not to mention what kind of crime. There are also a chengyu, 以毁为罚yǐ huǐ wéi fá, mean that the punishment should be measured according to his crime.

This site will help you in future;
Dictionary of more than 30 000 Chengyu (chinese proverbial idioms) with calligraphy, pinyin, english translation, chinese explanations, synonyms, ...
www.chinese-tools.com/chinese/chengyu/dictionary

可以說 罪刑相當 罪刑相稱 罰當其罪 或者 依罪量刑 依罪科罰
依罪量刑 可能比較接近你的期望