Although not a certainty, presence of retroactive provisions or potentially retroactive provisions is likely to raise questions of constitutionality. Research on the operation of a statute should always include an examination of both the statute and any amendments to assess their possible retroactive effects. If so, additional research into the relevant dates of events, enactment and amendment may give rise to rights and remedies for the client.
Legislative intent notwithstanding, the court may not give a statute retroactive effect if doing so offends constitutional principles. In re Marriage of Buol, 39 Cal.3d 751, 756 (1985).
In determining whether a retroactive law contravenes the due process clause, we consider such factors as the significance of the state interest served by the law, the importance of the retroactive application of the law to the effectuation of that interest, the extent of reliance upon the former law, the legitimacy of that reliance, the extent of actions taken on the basis of that reliance, and the extent to which the retroactive application of the new law would disrupt those actions.
In re Marriage of Petropoulos, 91 Cal.App.4th 161, 174 (2001), quoting In re Marriage of Bouquet, 16 Cal.3d 583, 592-93 (1976). Thus, courts have been unsympathetic to retroactive legislative denial of rights to reimbursement for previously incurred debts. See, e.g., County of Sacramento v. Loeb, 160 Cal.App.3d 446, 459-60 (1984) ("As the Counties' contractual entitlement to the money arose at least in 1980-1981, if not before, application of a statute enacted in 1983 which purports to cut off that entitlement would clearly be retroactive" and would not be enforced.). Retroactive changes to statutes of limitation may trigger constitutional violations, E.g., Lampf, Pleva, Lipkind, Prupis & Petigrow v. Gilbertson, 501 U.S. 350 (1995) (superseded by statute). Even a new rule of constitutional law may trigger violations if applied retroactively. E.g., Landgraf v. USI Film Products, 511 U.S. 244 (1994); Teague v. Lane, 489 U.S. 288 (1989); Bender, The Retroactive Effect of an Overruling Constitutional Decision: Mapp v. Ohio, 110 U. Pa. L. Rev. 650, 655-56 (1962).