It's not just the lack of a second amendment; it's a lack of a comprehensive bill of rights, and the institutional values that go along with that. Other than namby-pamby hand waving about human rights, the Australians simply do not have any concrete constitutional protections for individual liberty built into their constitution. And more's the pity, since they basically cribbed their constitution from the U.S. Constitution, and intentionally chose not to add a bill of rights for reasons that, as the present is now demonstrating, were clearly inadequate.