Not all laws are legitimate. We can see that many laws in the past have not been legitimate, such as those allowing slavery or the killing of infants. But how can we discern whether our current or considered laws are legitimate? Although not an exhaustive list, these 12 criteria, derived from examination of the functions and foundations of law, can aid us in discerning the legitimacy of any particular law.

1. A law must fulfill its functions.

The functions of law are justice and order, justice being primary. Therefore, law must serve a function of order or justice or both, while always placing justice above order. A law which does not serve either or places order above justice has no legitimacy, as it does not fulfill its functions correctly and thus defeats its very purpose.

2. A law must not be contrary to moral principles.

Since justice is based on morality, and law’s primary function is to maintain justice, a law which is contrary to moral principles cannot fulfill its primary function and is therefore illegitimate.

3. A law must be prescribed by a legitimate governing authority.

Even otherwise good laws cannot be binding if they are not issued by a legitimate governing authority, otherwise we might be bound to competing “laws” created by different people and organizations.

4. A law must be knowable.

A law that cannot be easily known cannot be intentionally followed. A law that cannot possibly be intentionally followed cannot be legitimate.

5. A law must be understandable.

If the average citizen cannot understand a law by which he is supposed to be bound, he cannot follow such a law. Consequently, such a law loses its legitimacy. If more complex scientific concepts like gravity, germ theory, electricity and radiation are understandable to the average person when explained in layman’s terms, then what excuse does the law have for not being understand to those who are supposed to follow it?

This is not an excuse for ignorance. It puts the onus both on lawmakers and citizens. Lawmakers must write laws so that they are generally understandable, and citizens must honestly and seriously seek to understand the law. If after such discernment, the average citizen is still not able to understand, and thus comply with the law, then it must not be considered legitimate.

6. A law must be specific.

Laws are by their very nature meant to be specific, because laws are specific implementations of the general principles of morality and order. If a law is too broad, then its boundaries become unclear, and it may be applicable to almost any situation or allow authorities to prescribe almost any penalty or action, since it is not sufficiently specified.

This creates a situation where the boundaries of law are unknown, and government authorities can simply do as they please anytime anywhere to anyone under the guise of rule of law. Even if this is not the intention, it robs any such law of legitimacy. A law that allows for anything, is one that is worth nothing. At its worse, this can become totalitarianism under the guise of law.

7. A law must be practical to enforce and to determine when it has been broken.

It is not enough for a law to be specific. There must also be a practical and ethical way of determining whether the condition specified has occurred and a way in which to enforce the law. If there is no way to determine the condition, there is no way to know whether the law has been followed or broken. If there is no way to enforce the law, there is no legal consequence for breaking it, thus making it irrelevant to the legal system upon which the law rests.

8. A law must not contradict a higher law nor undermine it’s own foundation.

A law can’t undermine the very foundation that it’s based on, for it would no longer have any foundation to stand on at all, and thus, it would have no legitimacy. This would be self-refuting. The law’s contradiction of its foundation would invalidate the law itself. For example, a law outlawing the U.S. Constitution would not be legitimate, because U.S. law depends on the Constitution for its legal foundation and validity.

9. A law must not exceed the jurisdiction of the governing body or its legal foundation.

Similarly, a law cannot exceed the jurisdiction of the government. For example, U.S. law has no legitimacy in France, because the U.S. government is not the legitimate governing authority in France (see #3). And, in the U.S., law cannot exceed the jurisdiction established by the U.S Constitution.

10. A law must be logical and grounded in reality.

Laws make conclusions about what it right or wrong, since they are based on the principles of order and morality. Those conclusions are based upon certain premises. For those conclusions to be logically valid, they must agree with the premises. For this we can use a syllogism, such as the following:

Premise 1: All crimes should be penalized.

Premise 2: Torture is a crime.

Conclusion: Therefore torture should be penalized.

In the above, the conclusion is valid, because it logically agrees with the premise. However, in addition to be logically valid, the premises must also be based in reality. Consider the following syllogism:

Premise 1: All crimes should be penalized.

Premise 2: Torture is not a crime.

Conclusion: Therefore torture should not be penalized.

The above syllogism is logically valid, because the conclusion logically flows from the premises. However one of the premises is simply not true. It is not based in reality. Torture is indeed a crime, and so should be penalized. Therefore we must check both whether the law is logical and whether its premises are truly grounded in reality and true.

11. A law must be necessary.

Following the law is not optional if it is legitimate law. This is what makes it a law rather than a suggestion. Additionally, law is enforced through the power of the state, which is not to be taken lightly nor applied unnecessarily.

If a law is not necessary, it is like your doctor telling you “You don’t really need this medicine, but you have to take it anyway.” The prescription of unnecessary laws and the use of force when unnecessary is highly unethical. Therefore, a law must be necessary to be legitimate.

12. A law must not be retroactive.

A law cannot take effect before it is enacted nor after it has been repealed. Therefore, a law cannot make criminals those who have not observed it before it was in effect, nor continue considering men criminals for violating said law after it has been repealed. Otherwise, it would be practically impossible to follow the law, since any given law could make us criminals even before it existed. Therefore, law must not be retroactive to be legitimate.