FACTS:

Albino Co issued a postdated check to a salvaging firm as payment for his share of salvage operations. The check was deposited but was later dishonored. Co was convicted of violating B.P. Blg. 22 and appealed the decision. He argued that a previous case should not be applied retroactively. The Court reinstated Co's appeal and mentioned that judicial decisions form part of the legal system and can have retroactive effect unless stated otherwise. Several cases were cited to illustrate instances where the principle of prospectivity was applied to statutes, administrative rulings, and judicial decisions. The Court also emphasized that laws shall not have retroactive effect unless otherwise provided.

ISSUES:

1. Whether the old doctrine should be applied prospectively and not retroactively.

2. Whether the retroactive application of a law is unconstitutional.

3. Whether or not an unconstitutional act, such as an executive order or a municipal ordinance, can serve as the source of any legal rights or duties and justify any official act taken under it.

4. Whether or not the existence of a statute prior to its declaration of nullity should be considered as an operative fact and have legal consequences.

5. Whether or not a decision declaring the unconstitutionality and invalidity of criminal proceedings during the martial law regime should be given retroactive effect, particularly in nullifying final judgments rendered by military courts against civilians.

6. Whether the defense of honest misconstruction of the law under legal advice is a valid defense in this case.

7. Whether the reliance on an official pronouncement of the Secretary of Justice can be a valid defense in this case.

RULING:

1. The Court ruled that when a doctrine of the Court is overruled and a different view is adopted, the new doctrine should be applied prospectively and should not apply to parties who had relied on the old doctrine and acted on the faith thereof.

2. The Court held that the retroactive application of a law usually divests rights that have already become vested or impairs the obligations of contracts, which is unconstitutional.

3. The Court held that an unconstitutional act, including an executive order or a municipal ordinance, cannot be the source of any legal rights or duties. It also cannot justify any official act taken under it. Once it is declared null and void by the judiciary, it is deemed to be a mere scrap of paper and loses any legal effect.

4. The Court recognized that while an unconstitutional act may have been in force and complied with prior to its declaration of nullity, its existence as a fact must be reckoned with. This is to ensure fairness and justice, as parties may have acted under it and changed their positions. However, the subsequent ruling of unconstitutionality may have to be considered in various aspects, particularly with respect to particular relations, individual and corporate, and particular conduct, private and official.

5. The Court ruled that the decision declaring the unconstitutionality and invalidity of criminal proceedings during the martial law regime should only be applied prospectively to future cases and ongoing or not yet final cases at the time of the decision's promulgation. Final judgments, whether of conviction or acquittal, rendered by military courts against civilians before the promulgation of the decision should not be retroactively nullified. Only in particular cases where there was a serious denial of constitutional rights of the accused should the nullity of the sentence be declared and a retrial ordered. If a retrial is no longer possible, the accused should be released since the judgment against them is null due to the violation of their constitutional rights and denial of due process.

6. The defense of honest misconstruction of the law under legal advice is a valid defense in this case.

7. Reliance on an official pronouncement of the Secretary of Justice can be a valid defense in this case.

PRINCIPLES:

• Legis interpretatio legis vim obtinet - the interpretation placed upon the written law by a competent court has the force of law.

• Judicial decisions applying or interpreting the laws or the Constitution shall form a part of the legal system of the Philippines.

• Laws shall have no retroactive effect unless the contrary is provided.

• Lex prospicit, non respicit - the law looks forward, not backward.

• The actual existence of a statute, prior to its nullification, is an operative fact that may have consequences which cannot justly be ignored.

• The retroactive application of a law usually divests rights that have already become vested or impairs the obligations of contract and is therefore unconstitutional.

• An unconstitutional act cannot be the source of any legal rights or duties and cannot justify any official act taken under it.

• Prior to the declaration of nullity, an unconstitutional act must have been in force and complied with, but its existence as a fact must be reckoned with. However, the subsequent ruling of unconstitutionality may have consequences that should be considered.

• The declaration of unconstitutionality and invalidity of criminal proceedings during the martial law regime should generally be applied prospectively, with final judgments rendered by military courts against civilians before the promulgation of the declaration not being retroactively nullified. Only in cases of serious denial of constitutional rights should the nullity of the sentence be declared and a retrial ordered. If a retrial is not possible, the accused should be released.

• The defense of honest misconstruction of the law under legal advice can be appreciated as a valid defense.

• Reliance on the official pronouncement of the Secretary of Justice, whose opinions are entitled to great weight, can be a valid defense.

• In criminal actions, all doubts must be resolved in favor of the accused.

• The principle of prospectivity, negating criminal liability, should prevail over the doctrine of mala prohibita.