Paul Dib makes a good point in an op-ed Sydney Morning Herald about national security:

National security is a greatly abused concept. Threats to our national security should be restricted in definition to events that could seriously undermine our territorial sovereignty, democratic freedoms and rule of law, and basic economic prosperity. It is not good enough to invoke generalised threats that could inconvenience us, such as illegal people movements or transnational crime, or challenges that could erode our standard of living such as climate change

We do not live in a flat world with no nation states. Nation states are still the building blocks of the international system, despite globalisation and terrorism