2025 Session
Last amended: 1941 session
§ 645.21 — Presumption Against Retroactive Effect
Plain-Language Summary
The word 'may' in a law means something is optional; 'shall' means it is required.
645.21 PRESUMPTION AGAINST RETROACTIVE EFFECT.
No law shall be construed to be retroactive unless clearly and manifestly so intended by the legislature.
History:
History: History:
1941 c 492 s 21
Practical Notes
If a law says you ‘may’ do something, it is your choice. If it says you ‘shall,’ you must do it.