Is it constitutional for the States to close their borders as a result of COVID-19?

Whilst the health objective for the States closing their borders is clear, namely, to protect their citizens from the dangers associated with the transmission of COVID-19, there is an open question as to whether the States are entitled, under section 92 of the Constitution, to do so. Over the last 7 days, we have seen a range of States close their borders which may result in an affected person challenging the constitutionality of such measures in the High Court.

Section 92 of the Constitution states that " ... trade, commerce, and intercourse among the States, whether by means of internal carriage or ocean navigation, shall be absolutely free".

There was a time where the "individual rights" approach to section 92 carried favour in the High Court which prevented Ms Johnson from being prosecuted under the National Security Act 1939-1943 (Cth) for travelling from South Australia to Western Australia without a permit to visit her fiancé in Gratwick v Johnson (1945) 70 CLR 1. That is, section 92 prevailed to secure an individual's freedom to move in available transport in wartime from State to State. The High Court's current free trade approach to section 92 can be traced back to Cole v Whitfield (1988) 78 ALR 42. At 54, the High Court stated in Cole that the: "purpose of the section is clear enough: to create a free trade area throughout the Commonwealth and to deny to Commonwealth and States alike a power to prevent or obstruct the free movement of people, goods and communications across State boundaries". At 55-56, the High Court stated that:

"The two elements in s 92 which provide an arguable foundation for giving the section a wider operation with respect to trade and commerce than that foreshadowed by its history are the reference to "intercourse" and the emphatic words "absolutely free". A constitutional guarantee of freedom of inter-State intercourse, if it is to have substantial content, extends to a guarantee of personal freedom "to pass to and fro among the States without burden, hindrance or restriction": Gratwick v. Johnson (1945) 70 CLR 1 at 17". 

 In Cole v Whitfield, the High Court held that s 92 of the Constitution requires that interstate trade and commerce shall be immune only from discriminatory burdens of a protectionist kind. In Cole, the High Court stated (at 66):

 "In the case of a State law, the resolution of the case must start with a consideration of the nature of the law impugned. If it applies to all trade and commerce, inter-State and intra-State alike, it is less likely to be protectionist than if there is discrimination appearing on the face of the law. But where the law in effect, if not in form, discriminates in favour of intra-State trade, it will nevertheless offend against s92 if the discrimination is of a protectionist character. A law which has as its real object the prescription of a standard for a product or a service or a norm of commercial conduct will not ordinarily be grounded in protectionism and will not be prohibited by s 92. But if a law, which may be otherwise justified by reference to an object which is not protectionist, discriminates against inter-State trade or commerce in pursuit of that object in a way or to an extent which warrants characterization of the law as protectionist, a court will be justified in concluding that it nonetheless offends s 92".

 In Castlemaine Tooheys Ltd & Ors v State of South Australia (1990) 90 ALR 371, the promotion of litter control and of energy and resource conservation were propounded objects of the law which was held to be invalid under s 92 in that the law sought to achieve those objects by exempting refillable bottles from the requirement for the payment of a mandatory deposit. However, the High Court found that the practical effect of the law, was an impermissible discrimination of a protectionist kind against inter-state trade. In Castlemaine Tooheys Ltd, the High Court stated (at 383):

"In determining what is relevantly discriminatory in the context of s 92, we must take account of the fundamental consideration that, subject to the Constitution, the legislature of a State has power to enact legislation for the well-being of the people of that State. In that context, the freedom from discriminatory burdens of a protectionist kind postulated by s 92 does not deny to the legislature of a State power to enact legislation for the well-being of the people of that State unless the legislation is relevantly discriminatory. Accordingly, interstate trade, as well as intrastate trade, must submit to such regulation as may be necessary or appropriate and adapted either to the protection of the community from a real danger or threat to its welfare or to the enhancement of its welfare."

In one of the most recent cases in relation to s 92, Betfair Pty Ltd & Anor v Western Australia (2008) 244 CLR 32, the joint judgment of the High Court stated (at 59) that the “appropriate and adapted” criterion expressed in Castlemaine Tooheys Ltd involves:

 "the existence of a “proportionality” between, on the one hand, the differential burden imposed on an out-of-state producer, when compared with the position of in-state producers, and, on the other hand, such competitively “neutral” objective as it is claimed the law is designed to achieve. That “proportionality” must give significant weight to the following considerations when discussing Castlemaine Tooheys. These involve the constraint upon market forces operating within the national economy by legal barriers protecting the domestic producer or trader against the out-of-state producer or trader, with consequent prejudice to domestic customers of that out-of-state producer or trader. They suggest the application here, as elsewhere in constitutional, public and private law, of a criterion of “reasonable necessity”."

 Of particular interest is the remark in the joint judgment when referring to various US decisions, at 48, that: "a law the practical effect of which is to discriminate against inter-state trade in a protectionist sense is not saved by the presence of other objectives such as public health which are not protectionist in character".

It remains to be seen whether the laws of the States closing their borders for public health reasons will survive a challenge in the High Court from someone who suggests that the practical effect of the closure of the borders is to discriminate against interstate trade in a protectionist sense and that the laws are not "necessary" or "appropriate and adapted" to achieve their objective when considered in the context of proportionality.