Walker had previously made similar arguments in a line of cases in Queensland: R v Walker (1988) QDC (unreported, June 1988, Skoien J); R v Walker  QSCCCA 177; and in requesting special leave for appeal to the High Court in Walker v R (1989).
In these cases, Walker had faced two criminal charges of damaging property. He argued that Queensland courts did not have jurisdiction to try him because the alleged activities occurred on Nunukel Country and so Nunukel law applied.
Walker's argument was that Captain James Cook's claim to British sovereignty over Australia was illegal because the Nunukel did not consent to it. Due to this, the Nunukel system of government and laws still applied. Mason CJ refused Walker's application, noting that although these questions were admittedly important, they had not first been determined in a lower court. It was therefore inappropriate for the High Court to consider the case.
The Court later decided in Mabo v Queensland (No 2)  HCA 23 ('Mabo (No 2)') that where Aboriginal title to land had not been extinguished by British settlement, it continued to exist.
In this case, Walker had been charged with six offences under NSW criminal law for maliciously discharging loaded firearms with intent to do harm or resist arrest, as well as assault a police officer in the execution of his duty. This alleged activity occurred on Bundjalung Country, at Nimbin.
Walker applied to the High Court of Australia for his summons to be dismissed.
Walker argued that the Commonwealth and state parliaments did not have the power to legislate in a way that applied to Aboriginal people without their request or consent.
Alternatively, he argued that a state law will have no effect until Aboriginal people adopt or accept it.
Walker argued in oral submissions that the effect of the decision in Mabo (No. 2) was that Aboriginal customary criminal law had survived British settlement in the same way the land tenure of the Meriam people continued to exist. Criminal statutes would therefore not apply to Aboriginal peoples.
The State of NSW brought an application by summons that Walker's claim be dismissed or alternatively stayed on the basis that there was no reasonable cause of action to answer.
Chief Justice Mason dismissed Walker's application as a single judge of the Court.
Details of the Judgment:
The key legal questions to be decided were:
- Whether the parliaments of the Commonwealth and the states have power to legislate in a manner affecting Aboriginal people without the acceptance, adoption, request, or consent of Aboriginal people?
- Whether Aboriginal criminal customary law survived British settlement and can co-exist with State criminal law?
In striking out the statement of claim and dismissing proceedings, Mason CJ held that:
- The NSW legislature has power to make laws for the peace, welfare, and good government of NSW in every instance. Applying Coe v Commonwealth  HCA 42, there is nothing in Mabo (No. 2) to suggest the parliaments of the Commonwealth and NSW do not have legislative competence to regulate or affect the rights of Aboriginal people or that these laws require Aboriginal persons to accept, adopt, request, or consent to them .
- The proposition that criminal legislation does not apply to Aboriginal people must be rejected. The basic principle that all people stand equal before the law would be offended if this proposition were to be accepted . There is no similarity between the criminal law and the decision in Mabo (No. 2) that native title could be held by Aboriginal people despite British settlement. Australian criminal law, as well as English law, does not accommodate an alternative body of law operating alongside it .