Public law is the branch that governs the relationship between the individual and the State, and two Latin maxims sit at its philosophical core. Salus populi est suprema lex — the welfare of the people is the supreme law — supplies the justification for the State to override private rights in the larger public interest, and it animates the police power, the doctrine of eminent domain, and much of modern environmental and public-interest jurisprudence. Rex non potest peccare — the King can do no wrong — is its mirror image and historical adversary: a feudal common-law fiction that once cloaked the sovereign in immunity from suit. This article traces how Indian courts have embraced the first maxim and steadily dismantled the second, so that today the welfare of the people is not merely the supreme law but also a weapon against the very State that invokes immunity. Read alongside the introduction to legal maxims and the legal maxims hub, it equips you to handle the public-law maxim questions that recur in judiciary and CLAT-PG papers.
What Public Law Maxims Mean
Maxims are condensed statements of legal principle, distilled over centuries of judicial reasoning into a memorable Latin phrase. In public law they perform a particular function: they capture the tension between collective welfare and individual right, and between State power and State accountability. Salus populi est suprema lex (sometimes rendered salus populi suprema lex esto, "let the welfare of the people be the supreme law") is a maxim of empowerment — it tells the State that it may act, even against private interest, where the safety and welfare of the community demand it. Rex non potest peccare is a maxim of immunity — it historically told the subject that the Crown could not be sued in its own courts for a wrong.
The two are not free-standing slogans but operate through concrete doctrines. The first underlies the police power of the State (the inherent authority to regulate for health, safety and morals), the doctrine of eminent domain (compulsory acquisition of private property for public purpose), and the modern law of public nuisance and environmental protection. The second underlies the common-law doctrine of sovereign immunity, which determined for a century whether a citizen injured by a government servant could recover damages. Understanding each maxim therefore means understanding the doctrine it carries and the case law that has shaped it.
Salus Populi Est Suprema Lex — Origin and Meaning
The maxim is generally traced to Cicero's De Legibus, where he wrote "salus populi suprema lex esto" — let the safety of the people be the highest law — as the guiding principle for magistrates. It passed into the common law through Coke and Blackstone and has been described as one of the two maxims (the other being necessitas publica major est quam privata, public necessity is greater than private) on which the whole edifice of the State's regulatory and acquisitory power rests. The literal sense is straightforward: where the welfare of the community and the interest of the individual collide, the former prevails.
It is important to read the maxim carefully. It does not authorise arbitrary State action; it authorises action for the welfare of the people. The welfare is the justification and also the limit. A measure that does not genuinely serve public welfare cannot shelter behind the maxim, and Indian constitutional law has built procedural and substantive safeguards — reasonableness under Article 14, the public-purpose and compensation requirements of eminent domain — precisely to keep the maxim from becoming a licence for expropriation. The maxim, in other words, is the engine of public power, but the Constitution supplies the brakes.
Salus Populi and the Doctrine of Eminent Domain
The clearest doctrinal home of salus populi est suprema lex in Indian law is the power of eminent domain — the sovereign's inherent right to take private property for a public purpose on payment of compensation. The doctrine rests on two maxims working together: salus populi est suprema lex and necessitas publica major est quam privata. Together they explain why the State may compel an unwilling owner to surrender land for a road, a dam, a hospital or a public housing scheme.
The post-Independence land-reform litigation is the great illustration. In State of Bihar v. Maharajadhiraja Sir Kameshwar Singh of Darbhanga (AIR 1952 SC 252), the Supreme Court considered challenges to the Bihar Land Reforms Act, 1950, which abolished the zamindari system. Although the right to property was then a fundamental right under Articles 19(1)(f) and 31, the Court recognised that the welfare of the community as a whole — the redistribution of agrarian holdings to achieve social justice and economic equality — could justify the deprivation of large private estates, subject to the constitutional conditions of public purpose and compensation. The decision is a textbook application of salus populi: the welfare of the many prevailing over the property of the few, but channelled through constitutional discipline rather than naked force.
The constitutional architecture itself reflects the maxim. The Forty-fourth Amendment, 1978 removed the right to property from the list of fundamental rights and relocated it as a constitutional/legal right under Article 300A ("No person shall be deprived of his property save by authority of law"), making it easier for the State to pursue welfare measures while still requiring legal authority for any deprivation. The maxim thus survives not as an abstraction but as the spine of acquisition law, now governed by the Right to Fair Compensation and Transparency in Land Acquisition, Rehabilitation and Resettlement Act, 2013.
Salus Populi in Police Power, Public Nuisance and Environment
Beyond acquisition, salus populi justifies the State's regulatory or police power — the authority to restrain individual liberty and property in the interest of public health, safety, morality and order. Quarantine and lockdown measures, demolition of unsafe structures, abatement of public nuisance, and prohibition of noxious trades are all exercises of this power, and each is defended on the footing that the welfare of the people is the supreme law.
Indian environmental jurisprudence has drawn heavily on the maxim. The Supreme Court's recognition of the polluter-pays principle and the public trust doctrine proceeds from the idea that the State holds natural resources for the benefit of the people and may regulate or extinguish private use that harms the community. In M.C. Mehta v. Kamal Nath ((1997) 1 SCC 388), the Court applied the public trust doctrine to set aside a lease of ecologically sensitive land, reasoning that certain resources are held by the State in trust for the public and cannot be alienated to private benefit at the cost of public welfare. The same logic — collective welfare overriding individual commercial interest — runs through the closure of polluting tanneries and the regulation of hazardous industry, and it connects this maxim to the equity-based reasoning you will meet in the maxims relating to justice.
Rex Non Potest Peccare — Origin and the Fiction of the Crown
Rex non potest peccare means "the King can do no wrong." It is a maxim of English feudal law expressing two distinct ideas that later fused. The first is that the King, being the fountain of justice, could not be sued in his own courts — there was no superior tribunal to compel him. The second is the constitutional fiction that the Crown is incapable of authorising or committing a legal wrong, so that any wrong done by a royal servant must be the servant's personal wrong, not the King's. From these ideas grew the common-law doctrine of sovereign immunity: the rule that the State is not liable in tort for the acts of its servants.
It is essential for the exam to grasp that the maxim and its immunity were creatures of a particular constitutional order — one in which sovereignty resided in the person of the monarch. In a republic where sovereignty resides in the people, the premise dissolves. As Indian courts came increasingly to recognise, once the people are sovereign there is no King who can do no wrong; there is only a State that serves the people and must answer to them. This insight is what ultimately reduced rex non potest peccare from a rule of immunity to a historical curiosity. The doctrinal distinction Indian courts used to mediate this transition — sovereign versus non-sovereign functions — is examined below.
Sovereign Immunity in India — The P&O Foundation
The starting point of Indian sovereign-immunity law is Peninsular and Oriental Steam Navigation Co. v. Secretary of State for India (1861) 5 Bom HCR App 1, decided by the Supreme Court of Calcutta. A servant of the P&O Company was injured when a piece of iron funnel being carried by government workmen for the repair of a steamer fell and startled the company's horses. Sir Barnes Peacock CJ drew the distinction that would govern Indian law for over a century: the State is liable for torts committed by its servants in the discharge of non-sovereign functions — those that could equally be carried on by a private individual — but not for torts committed in the exercise of sovereign functions, the acts that only a sovereign State can perform. Because maintaining a dockyard was a non-sovereign, commercial activity, the Secretary of State was held liable.
The P&O test thus imported a modified, narrower version of rex non potest peccare into India. It was never the full English immunity; from the outset Indian law accepted State liability for the large class of non-sovereign acts. The difficulty — which haunted the doctrine for the next century — was the slippery line between sovereign and non-sovereign functions, a line that proved increasingly artificial as the modern welfare State expanded into trade, transport and industry.
State of Rajasthan v. Vidhyawati — Liability Affirmed
The first great post-Constitution pronouncement was State of Rajasthan v. Mst. Vidhyawati (AIR 1962 SC 933). A temporary government driver, employed under the Collector of Udaipur and driving a State jeep back from the workshop after repairs, negligently knocked down a pedestrian, Jagdishlal, who died of his injuries. His widow sued the State. A Constitution Bench held the State of Rajasthan vicariously liable, observing that in a democratic republic that had abolished the privileges of the Crown, there was no justification for placing the State on a higher footing than an ordinary employer. The Court pointedly noted that the immunity of the Crown in the United Kingdom rested on the old feudal notion that the King can do no wrong — a notion wholly out of place under the Indian Constitution.
Vidhyawati is significant because the offending act — driving a vehicle — was plainly a non-sovereign function, so the result sat comfortably within the P&O framework. But the tone of the judgment went further, signalling that the constitutional commitment to State accountability should narrow immunity to the vanishing point. Had the Court's reasoning prevailed unqualified, the maxim rex non potest peccare would have been buried in 1962. As the next case shows, that did not happen — at least not immediately.
Kasturilal — The High-Water Mark of Immunity
The doctrine's most criticised application is Kasturilal Ralia Ram Jain v. State of Uttar Pradesh (AIR 1965 SC 1039). Kasturilal, a partner in a firm of jewellers, was arrested in Meerut on suspicion of possessing stolen property, and a large quantity of gold and silver was seized from him and kept in police custody. He was later released, but the gold was never returned — a head constable had misappropriated it and absconded to Pakistan. The firm sued the State for the value of the gold lost through the negligence of the police in keeping it.
A Constitution Bench, speaking through Gajendragadkar CJ, refused relief. It held that the power to arrest, search and seize is a sovereign power delegated to the police, and a tort committed in the exercise of such delegated sovereign power does not render the State liable, even though the negligence in safekeeping was manifest. The Court applied the P&O distinction with full rigour: because the seizure flowed from sovereign police authority, immunity attached. The decision is widely regarded as the high-water mark of sovereign immunity in India and has been heavily criticised for producing an unjust result — a citizen left uncompensated for property lost through the State's own negligence — on the strength of a feudal fiction. Notably, the Court itself expressed unease, suggesting that legislation should be enacted to regulate State liability. The procedural and evidentiary dimensions of such claims connect to the points covered in the maxims relating to court proceedings.
Judicial Dilution — Nagendra Rao and the Retreat of Immunity
Although Kasturilal was never formally overruled, it was steadily emptied of content. The decisive blow came in N. Nagendra Rao & Co. v. State of Andhra Pradesh (AIR 1994 SC 2663). Officials had seized large stocks of fertiliser and foodgrains from a licensed dealer under essential-commodities controls; when the goods were eventually returned after prolonged official delay, they had deteriorated and lost value. The dealer sued the State for the loss caused by negligent custody.
The Supreme Court held the State liable and, in doing so, comprehensively reappraised the sovereign-immunity doctrine. The Court reasoned that in a modern welfare State the distinction between sovereign and non-sovereign functions has lost most of its meaning; the only functions that can be regarded as inalienably sovereign are those few that no private person can perform — the defence of the realm, the administration of justice, the maintenance of law and order in its core sense, and the legislative and treaty-making powers. Outside that narrow category, the State, like any employer, is answerable for the negligence of its servants. The Court was emphatic that the old immunity, rooted in rex non potest peccare, could not survive in a republic where sovereignty vests in the people. Nagendra Rao thus restored and extended Vidhyawati and confined Kasturilal to its facts.
The practical significance of this retreat is considerable. After Nagendra Rao, a litigant injured by negligent State action can no longer be defeated by a reflexive plea of sovereign immunity; the State must show that the impugned act falls within the genuinely inalienable core of sovereignty, and very few acts qualify. Routine governmental activity — running hospitals and transport, storing seized goods, maintaining public works, operating revenue and licensing machinery — is treated as ordinary employer activity for which the State answers in damages. The maxim rex non potest peccare, which began life as an absolute shield, has thus been reduced to a narrow and rarely available exception, surviving chiefly for acts such as military operations and the core administration of justice. For exam purposes the lesson is to state the modern position with precision: immunity is the exception, liability the rule, and the burden lies on the State to bring itself within the shrinking sovereign category.
The Constitutional Tort — Immunity No Defence to Rights Violations
The most powerful modern erosion of rex non potest peccare came not from the law of torts at all but from constitutional law. The courts developed the public-law remedy of compensation for violation of fundamental rights, awarded under Articles 32 and 226, and held squarely that sovereign immunity is no defence to such a claim. The watershed was Smt. Nilabati Behera v. State of Orissa ((1993) 2 SCC 746), arising from the custodial death of Suman Behera, found dead on a railway track after being taken into police custody. The Supreme Court awarded the mother Rs. 1,50,000 as compensation and held that the defence of sovereign immunity, available in a private-law action for damages in tort, has no application in a public-law proceeding for enforcement of fundamental rights. Liability of the State for breach of Article 21 is a distinct, strict liability founded on the constitutional obligation to protect life and personal liberty.
The seed had been sown in Rudul Sah v. State of Bihar ((1983) 4 SCC 141), where the Court awarded compensation to a man detained for fourteen years after his acquittal, and in Bhim Singh v. State of Jammu & Kashmir (AIR 1986 SC 494), where an MLA was unlawfully detained by the police to prevent him attending an Assembly session and the Court awarded Rs. 50,000 as exemplary monetary compensation for the breach of his rights under Articles 21 and 22(2). In D.K. Basu v. State of West Bengal ((1997) 1 SCC 416) the Court consolidated this jurisprudence, laying down custodial-rights guidelines and reaffirming that monetary compensation in the public-law domain is a remedy against which sovereign immunity cannot be pleaded. The cumulative effect is that for the most serious wrongs of the State — those that violate fundamental rights — the maxim rex non potest peccare is wholly displaced.
The Two Maxims in Tension
Read together, the two maxims describe the modern balance of public law. Salus populi est suprema lex empowers the State to act, and even to override private right, in the genuine interest of the community. Rex non potest peccare once shielded the State from answering for the harm its action caused. The trajectory of Indian law has been to strengthen the first while dismantling the second — to insist that the State may indeed pursue the public welfare, but must answer for the wrongs it commits in doing so.
This is not a contradiction but a coherent settlement. A State that may invoke public welfare to take property or restrain liberty acquires, by that very power, a heightened duty of care toward those it governs; immunity for the abuse of such power would be intolerable in a constitutional democracy. The maxim of welfare and the maxim of accountability are therefore complementary: the first justifies State power, the second disciplines it. The student who can articulate this relationship — power justified by salus populi, accountability secured by the collapse of rex non potest peccare — has grasped the heart of public-law maxims.
Exam Strategy and Common Traps
For the judiciary and CLAT-PG papers, anchor each maxim to its doctrine and its leading cases. For salus populi est suprema lex, remember eminent domain, the police power, and the public trust doctrine, with Kameshwar Singh and M.C. Mehta v. Kamal Nath as illustrations, and the shift of property from a fundamental right to Article 300A by the Forty-fourth Amendment. For rex non potest peccare, master the chronological chain: P&O (1861, sovereign/non-sovereign distinction), Vidhyawati (1962, liability affirmed), Kasturilal (1965, immunity's high-water mark), Nagendra Rao (1994, immunity narrowed), and the constitutional-tort line of Rudul Sah, Bhim Singh, Nilabati Behera and D.K. Basu.
The commonest trap is to assert that Kasturilal has been overruled — it has not; it has been confined to its facts and rendered largely inapplicable, which is a different and more accurate statement. A second trap is to confuse the private-law tort remedy (where immunity may still be argued for genuinely sovereign acts) with the public-law constitutional remedy (where immunity is no defence at all). A third is to treat salus populi as an unqualified licence for State action; always note the constitutional limits of reasonableness, public purpose and compensation. For the broader technique of pinning maxims to authority, revisit the introduction and the legal maxims hub.
Frequently asked questions
What does salus populi est suprema lex mean and where is it applied in Indian law?
It means "the welfare of the people is the supreme law." In Indian law it underlies the State's police power, the doctrine of eminent domain (compulsory acquisition for public purpose), and environmental doctrines such as the public trust principle applied in M.C. Mehta v. Kamal Nath. It justifies overriding private right for genuine public welfare, subject to constitutional limits of reasonableness, public purpose and compensation.
What does rex non potest peccare mean?
It means "the King can do no wrong." It is the feudal common-law source of the doctrine of sovereign immunity — the rule that the State is not liable in tort for the acts of its servants. The premise is that sovereignty rested in the King; in a republic where sovereignty rests in the people, Indian courts have held the maxim has no place, and it has been progressively displaced.
Has Kasturilal v. State of UP been overruled?
No. Kasturilal Ralia Ram Jain v. State of U.P. (AIR 1965 SC 1039) has never been formally overruled, but it has been confined to its facts and rendered largely inapplicable. N. Nagendra Rao & Co. v. State of A.P. (AIR 1994 SC 2663) narrowed the sovereign-function category to a tiny core, and the constitutional-tort cases hold sovereign immunity to be no defence to fundamental-rights violations. Saying it is "overruled" is an exam error.
What is the difference between sovereign and non-sovereign functions?
The distinction comes from P&O Steam Navigation Co. v. Secretary of State (1861). Sovereign functions are those only a sovereign State can perform — defence, administration of justice, core law and order, legislation, treaty-making. Non-sovereign functions are those a private person could also carry on, such as running a commercial dockyard or driving a vehicle. The State was traditionally immune for the former and liable for the latter, but Nagendra Rao shrank the sovereign category drastically.
Can the State plead sovereign immunity in a case of custodial death?
No. In Nilabati Behera v. State of Orissa ((1993) 2 SCC 746) the Supreme Court held that sovereign immunity is no defence to a public-law claim for compensation under Articles 32 and 226 for violation of fundamental rights. Liability for breach of Article 21, as in a custodial death, is a strict constitutional liability distinct from the private-law tort action where immunity might otherwise be argued.
How did the right to property change under salus populi reasoning?
Property was originally a fundamental right under Articles 19(1)(f) and 31. To enable land reform and welfare measures — as upheld in State of Bihar v. Kameshwar Singh (AIR 1952 SC 252) — the State needed wider power to acquire property. The Forty-fourth Amendment, 1978 removed property from fundamental rights and recast it as a constitutional right under Article 300A, reflecting the salus populi priority of public welfare while still requiring authority of law for any deprivation.