Doctrine of Necessity and the Doctrine of Efficacy: An easier version

Ever heard something bizarre like ‘It worked, so it’s law’? Imagine a situation where country's constitution gets thrown out a window, and someone in a “black robe” has to decide whether to call the police or applaud. Think of two of constitutional law's most quietly scandalous doctrines: the Doctrine of Necessity and the Doctrine of Efficacy. Together, they form the legal equivalent of a ‘gesture’ followed by a “signature” — the mechanism by which courts have, again and again, blessed what should, on paper, be illegal.

Necessity: The old "I had no choice" excuse

The idea of "necessity" comes from an old Latin saying meaning "necessity has no law." At first, it was used for small, understandable things like a starving sailor eating a dead shipmate to survive, or a doctor treating an unconscious patient without asking permission first. Old English writers put it politely: what is not lawful in law, necessity makes lawful. A narrow escape hatch, meant for genuinely desperate moments.

But lawyers later used this same idea for something much bigger: excusing governments that broke their own constitutions. The most famous example is from Pakistan, in cases from the 1950s, where courts basically said: "Yes, what happened was against the rules. But the country needed saving, so we'll allow it after the fact." The reasoning goes like this — if strictly following the constitution would make the government collapse, then breaking the rules to save the country can be forgiven, like a form of self-defense. (Funny but please accept it!)

It is worth knowing how that actually happened, because it was not an accident. In 1954 the Governor-General of Pakistan dissolved the Constituent Assembly. The Assembly's President went to court and won at the Sind Chief Court. Then the Federal Court, led by Chief Justice Muhammad Munir, reversed it on a technical point. Shortly afterwards, in an advisory reference, the same court reached for a Latin phrase — salus populi suprema lex, the welfare of the people is the supreme law — and used it to validate what the Governor-General had done. One maxim, quietly borrowed from a very different context, and a constitutional crisis was tidied away.

Efficacy: The "did it actually work?" test

If necessity is about emotion — "we had to do it!" — efficacy is the cold, practical version. This idea comes from legal thinker Hans Kelsen. It doesn't ask if a takeover was fair or necessary. It only asks one thing: did it work? Is the new government actually in control?

Kelsen believed every legal system is built on one basic assumption (he called it the "Grundnorm") that makes all other laws valid. If a coup or revolution succeeds — meaning the old government is truly gone and people generally obey the new one — then that basic assumption shifts too. The old constitution isn't just broken; it's replaced. The new government becomes "legal" simply because it's now functioning. In other words, power alone doesn't make something right — but according to this theory, it can make it official.

This theory got its most famous courtroom outing in Pakistan in State v. Dosso (1958), decided days after a military takeover. The court held that a successful revolution is itself a law-creating fact. A new order had arrived, people were obeying it, so it was valid. Case closed.

Here is the uncomfortable footnote: Kelsen was writing legal theory, not handing judges a checklist. He was trying to describe how legal systems are understood from the outside, not to give courts a licence to certify whoever wins. Turning a philosopher's description into a judicial test was the work of lawyers, not of the philosopher. That single move did an enormous amount of damage across several countries.

How the two ideas work together

Courts rarely use these two ideas separately. Usually, efficacy provides the reasoning, and necessity provides the excuse. First, a court checks: has the new government actually taken control? If yes, efficacy says the new system counts as law. Then necessity kicks in to explain why the court should go along with it instead of resisting.

But later court cases pushed back hard on this. In Pakistan's 1972 case Asma Jilani, judges rejected the earlier approach, saying that just because someone successfully grabs power doesn't make them a legitimate ruler — otherwise, it's just "organized crime with a flag." Courts in Bangladesh also limited how necessity could be used, insisting it should only apply in rare, temporary emergencies — not as a permanent excuse for future takeovers.

The Doctrine That Refuses to Die

Rejecting a doctrine, unfortunately, is not the same as burying it.

Five years after Asma Jilani, the same Pakistani court was back at it in Begum Nusrat Bhutto (1977), this time validating another takeover on grounds of — you guessed it — necessity. In 2000 it happened again. The pattern is almost comic if you ignore the human cost: condemn the doctrine in one decade, quietly reopen the file in the next.

It also travelled. Courts in Uganda, Nigeria, Grenada, Cyprus and elsewhere all found themselves reaching for the same vocabulary. And once in a while a court refused. In Fiji in 2001, the judges looked at exactly this argument and declined to certify a takeover, holding that the old constitution was still standing. It is a reminder that none of this is automatic. Judges have a choice. They have always had a choice.

Bangladesh's Own Encounter

Our courts eventually took a sharper position, and in a very specific way.

In the case widely known as the Fifth Amendment Case, the High Court Division in 2005 held that the martial law regime of 1975 to 1979, and the constitutional amendment that had validated it, were unlawful. The Appellate Division upheld that view in 2010. A similar reckoning followed for the martial law period of the 1980s in the Seventh Amendment Case.

But notice what the courts did next, because this is where necessity quietly returns in a different costume. Having declared those regimes illegal, the judges did not unravel everything done during them. Ordinary administrative acts, appointments, and transactions were condoned — accepted as valid — precisely to avoid chaos. The regimes were illegitimate; the daily life that went on under them was allowed to stand.

That is necessity, doing careful, limited, defensible work. Not validating a usurper, but preventing a legal vacuum. It is the difference between using an escape hatch and living in it.

Concluding Remarks

Necessity and efficacy aren't really two separate legal rules — they're more like two partners in an old trick. Efficacy explains what happened. Necessity explains why it's okay that it happened. Today's courts, having seen this excuse used and abused many times, are much more cautious — treating both ideas as useful only in real emergencies, and dangerous if they become a regular habit.

For a law student, the takeaway is not the Latin. It is this: constitutional law does not run itself. Every one of these cases came down to a bench deciding whether to ask the hard question or the easy one. Was this lawful? is the hard question. Is he in charge now? is the easy one. History has been fairly clear about which courts are remembered well.