I want to know how to say as Thomas Jefferson said "when law becomes tyranny rebellion becomes duty" in Chinese but with as few signs as possible, traditional Chinese or simplified whichever is the shortest. I'm thinking of maybe getting a tattoo with it.
Edit: Besides idiom and classical style, using a slogan is also a way to reduce text
full sentence: 反抗暴政是每一個人的責任
Both mean "Resisting tyranny is everyone's responsibility"
Further reduce: 抗暴政，民有責 (Resisting tyranny is the people's duty)
What you are looking for is an idiom or literary classical-style speech. Compare to the modern Chinese colloquial language, classical can express a full sentence with as few as one or two words, and some idioms can contain an entire story or ideology
There is an idiom 官逼民反 (When government persecutes the people, the people will revolt). It might be the phrase you wanted
"官逼民反" in modern Chinese would be "政府迫害人民，人民就會反抗"
The exact quote: "when law becomes tyranny rebellion becomes duty" in modern Chinese is "當法律變成暴政時，反叛就變成了責任".
Using classical-style speech, you can reduce it to "政暴則責在必反" (when the law is tyrannic, one's duty is to revolt)
政 - government/ law
苛 - tyrannic
則 - then
責在 - duty dictate
必反 - must revolt
In the Declaration of Independence, Jefferson (slave owner and racist), referring to the despotic British, said:
When faced with a “long train of abuses” with the goal of pursuing despotism, it is the duty of the people to “throw off such government.”
That has been variously interpreted.
Rebellion is a duty when the government becomes an oppressor.