The Doctrine of Pith and Substance in Pakistan

The doctrine of pith and substance is a principle of constitutional interpretation used in federations to determine the true subject matter of legislation. Originating in Canadian jurisprudence and adopted in British-Indian law, it was later absorbed into Pakistan’s constitutional law. In essence, when a law’s validity is challenged as being outside the legislature’s competence, courts look at the law’s pith and substance, its true object and purpose, rather than its incidental overlaps with subjects outside that legislature’s domain. If in substance the legislation falls within the lawful field of the enacting legislature, it will be upheld even if it incidentally encroaches on matters within the other legislature’s jurisdiction. Minor or incidental intrusions into the other’s domain are tolerated so long as the law’s dominant character is within the proper authority’s sphere. Each topic in the legislative lists is treated as a “field” of legislation to be interpreted broadly, not narrowly or pedantically. This ensures a practical, flexible division of powers, preventing laws from being struck down merely due to peripheral overlaps.

Pakistani courts have long embraced pith and substance to navigate the division of powers between the Parliament (federal legislature) and Provincial Assemblies. Under successive constitutions (1935 Act, 1956, 1962, and 1973), legislative powers were allocated via lists (Federal, Provincial, and previously a Concurrent List), and courts used this doctrine to resolve competence disputes. The rule is that if a law in substance falls under a subject within one legislature’s jurisdiction, it is valid, even if it incidentally touches on a topic in the other legislature’s list. Only when a law’s true nature lies outside the enacting body’s powers will it be declared ultra vires. Pakistani jurisprudence imported examples from privy council precedents for instance, tax laws or regulatory laws have been upheld by characterizing their primary subject within the proper list and treating any overlap as ancillary. Over time, courts also acknowledged the “doctrine of occupied field” (or repugnancy): if the central legislature has validly occupied a field, a provincial law on the same subject would be invalid to the extent of conflict (and vice versa, where applicable). Notably, the occupied field idea is considered a corollary of pith and substance, it only applies when both legislatures legislated on the same subject matter in competition. If a supposed conflict is merely in form and the laws are in pith and substance on different subjects, the occupied field doctrine won’t be invoked. Courts thus first determine the law’s true subject and then see if a conflict in competence actually exists.

Early Pakistan case law, such as Tariq Transport Co. v Sargodha-Bhera Bus Service (SC 1958) and others, implicitly applied pith and substance when interpreting legislative competence under the 1956 Constitution. A later notable case is Hirjina & Co. v Pakistan (SCMR 1993), where the Supreme Court upheld a federal excise law by finding that in substance it fell within an entry of the 1962 Constitution’s federal list (validating a 1944 Act). In recent years, after the landmark 18th Amendment (2010) which abolished the Concurrent List and expanded provincial powers, pith and substance analysis became even more crucial. Courts faced questions of whether existing federal laws on now-devolved subjects could continue, or whether provinces could legislate new laws on those subjects. For example, in Pakistan Int’l Freight Forwarders Assoc. v. Province of Sindh (2017 PTD 1 Sindh), the Sindh High Court had to decide whether a provincial sales tax on services law conflicted with a federal excise duty on services. The court determined that both laws taxed the same event, and since “there is no concurrent taxing power” in Pakistan, only one level of government could levy the tax. By examining the pith and substance of the statutes, the court concluded the taxation of services after 18th Amendment fell in the provincial domain, upholding the Sindh Sales Tax Act 2011 and invalidating the overlapping federal Excise Act (2005) in that field. Similarly, in Asmat Ullah v. Govt of KPK (Peshawar High Court, 2019), the vires of the Khyber Pakhtunkhwa Control of Narcotic Substances Act 2019 were challenged on grounds that a federal law (Control of Narcotic Substances Act 1997) already “occupied the field” of narcotics control. The High Court applied Article 142 and 143 of the Constitution and found that after the 18th Amendment, “narcotics” was not enumerated in the Federal Legislative List. In pith and substance, it fell in the residuary provincial domain, meaning the provincial assembly was competent to enact the 2019 law. The court held this was not a case of an occupied field by the federation, so the new KPK law prevailed in the province and the federal 1997 Act’s application there “has been repealed” to the extent of inconsistency. These cases illustrate the doctrine’s function: the judiciary looks beyond superficial overlap and asks, what is the law essentially about, and who has authority over that matter? If the core falls in the legislature’s own sphere, the law stands (and any conflicting law by the other government yields to the extent of conflict).

The judiciary’s use of pith and substance remains vital in Pakistan’s evolving federalism. After 2010’s devolution, courts wrestled with how to treat pre-18th Amendment federal laws on subjects now devolved. Justice Munib Akhtar (then of Sindh High Court) authored a series of judgments mapping out legislative fields post-amendment, often invoking pith and substance to decide if federal laws could continue or if provincial laws should override. While the doctrine provides a bright-line rule favoring exclusivity, there is contemporary discussion of cooperative federalism as an interpretive approach that sometimes allows both federal and provincial involvement in a matter. This can create tension with the rigidity of pith and substance, especially in areas like environmental regulation or energy, where effective governance may require cooperation rather than clear-cut separation. Nonetheless, as of 2025, Pakistani courts continue to apply the pith and substance test as the primary means of resolving jurisdictional conflicts, ensuring that each tier of government legislates within its constitutional remit. The Supreme Court and High Courts have consistently upheld that a law’s constitutionality must be judged by its true character. In doing so, they preserve Pakistan’s federal balance, preventing trivial overlaps from invalidating laws while still policing the boundaries of legislative authority.