6.4 Presumption against Retrospective Legislation

The presumption: the statute not retrospective UNLESS the clear expression — the general words prospective-only (the enactment's date as the operation's start (Unit 3.1.2's companion)); the rationale: the fairness (the past's non-punishment; the vested rights' protection); the nuances: (i) the procedural statutes' retrospectivity (the procedure's immediate application — the pending proceedings' new procedure (the substance-procedure distinction)); (ii) the declaratory statutes' relation (the true-declaration read as always-the-law — the "retrospection" as the clarification); (iii) the vested rights' strict protection (the acquired rights' non-disturbance without the express command); the Nepal craft (the 2010 Act's savings; the penal laws' prospectivity (the legality principle (nullum crimen) — the retroactive punishment's constitutional bar's kinship)).