Article 20

Article 20 protects any person, citizen or not, against arbitrary and excessive punishment, and — notably — it is one of the two Fundamental Rights (with Article 21) that cannot be suspended even during a National Emergency, since the 44th Amendment amended Article 359 to say so.

• 20(1) No ex-post-facto law: no person can be convicted of an offence except for violating a law in force at the time of the act, nor subjected to a penalty greater than what that law prescribed at that time. This bars retrospective criminal legislation, though it does not bar retrospective civil legislation or a retrospective increase in the limitation period.
• 20(2) No double jeopardy: no person can be prosecuted and punished for the same offence more than once. This is narrower than the American "double jeopardy" clause — it protects against a second prosecution and punishment, not merely a second prosecution, and only where there has already been both.
• 20(3) No self-incrimination: no person accused of an offence can be compelled to be a witness against himself. In Selvi v. State of Karnataka (2010), the Supreme Court held that involuntary administration of narco-analysis, brain-mapping and polygraph tests violates Article 20(3) (and Article 21), since compelling a person to reveal information through such techniques amounts to testimonial compulsion.

Memory hook — "EDS, never suspended": Article 20's three protections spell E-D-S: Ex-post-facto protection (20(1)), Double jeopardy protection (20(2)), Self-incrimination protection (20(3)). Picture a prisoner who cannot be tried under a law that Emerged after his act, cannot be Dragged to court twice for the same offence, and cannot be made to Speak against himself — "EDS" also happens to be the only rights (with Art. 21) that survive even a National Emergency, so tag EDS mentally as "the un-suspendable trio's cousin."

Practice Recall: Before reading on, try to name Article 20's three protections and say which one applies even without a completed prosecution.

Answer: (1) No ex-post-facto conviction/penalty, (2) No double jeopardy (prosecution + punishment twice), (3) No compelled self-incrimination — the third, self-incrimination, is the one that doesn't require a prior prosecution or punishment to apply.