An odd thing happened last week in the wake of the Treasurer’s extraordinary decision to block State Grid and Cheung Kong Infrastructure from bidding for the NSW electricity distribution asset Ausgrid: the decision received little in the way of negative coverage from the press gallery.

This is not a government, and Scott Morrison is not a Treasurer, receiving a rails run from the media; at the moment, in fact, virtually everything the government does is viewed critically in either policy or political terms, or both. But the Ausgrid decision — which combined complete inconsistency from the government, kowtowing to xenophobia and economic nationalism and a refusal by Morrison to offer any reasons — copped little flak.

It soon became clear why: senior journalists had been backgrounded by the government on the basis for the decision and the apparently strong view of security agencies that it would be a national security risk to allow Ausgrid to be bought by foreign (read: Chinese) interests. National security agencies now play a stronger role in foreign investment approval decisions: the government has appointed the former ASIS and ASIO head David Irvine to the Foreign Investment Review Board and, stung by US criticism of the Darwin port sale decision, strengthened internal and external consultation processes around infrastructure sales. Nonetheless, it remains unexplained why it was OK for State Grid to bid for another NSW asset, Transgrid, last year, or buy other assets, or why no one has had a problem with Chinese billionaire Li Ka-Shing’s Cheung Kong Infrastructure buying power, gas and telecommunications assets across Australia until now. But criticism of the decision mainly came from respected economic and business journalists like Michael Pascoe, John Durie or (today) Alan Mitchell.

The hawkish view, of course, is that the Chinese might use Ausgrid to spy on Australian communications despite it not owning communications infrastructure, or perhaps want to shut down Ausgrid in the event of some sort of conflict. We’ve been pumping more and more money into cybersecurity in recent years on the basis that hackers anywhere in the world could access or bring down our critical infrastructure unless we gave the cyber military industry lots of money — without being too concerned about who specifically owned it. In fact, we had a cybersecurity strategy in 2009 and a defence white paper this year that both emphasised the “cyber threat” to critical infrastructure — without mentioning ownership at all. Suddenly, it seems, ownership is fundamental to security.

One veteran journalist, however, was having none of this. Brian Toohey gave both the decision and the ensuing media coverage both barrels on Monday, displaying exactly the kind of scepticism about the claims of security agencies — or more accurately what self-interested politicians insisted were the claims of security agencies — that every journalist should have shown.

The reason why they didn’t is that the term “national security” is designed to counter rational thought. Invoke “national security” and normal economic considerations — such as identifying the cost of a military incursion, or encouraging foreign investment — are abandoned. And it has the effect of stopping dead normal media scrutiny — as Morrison did about the Ausgrid decision, politicians are allowed to get away with invoking “national security” as a reason for rejecting perfectly normal questions from the media. Indeed, the Australian media has a strong tradition of allowing politicians to avoid scrutiny simply by invoking national security (witness the entire non-debate about the Snowden revelations in Australia) while politicians readily leak national security information that serves their own interests.

So potent is “national security” as a mechanism for suspending scrutiny, other sectors have tried to co-opt the idea to exploit its effects. “Food security”, for example, has long been used by agribusiness, Labor, the Greens and the Nationals to justify handouts to and regulatory restrictions for agriculture and agribusiness in Australia — including banning Chinese bidders from buying Australian agricultural companies.

Last week former prime minister Tony Abbott, in his speech to the right-wing Samuel Griffith Society that set out what a second Abbott prime ministership would look like, developed the idea of “economic security”, which has hitherto been a term more related to the fragile economic position of social groups. “The challenge for the new parliament will be to be as sensible about economic security as the old one was about national security,” Abbott said, in effect calling for bipartisanship on the budget. That is, Labor should abandon opposition to spending cuts for the same reason it didn’t oppose his national security “reforms”. Again, the point is to use the word “security” to short-circuit rational thinking and scrutiny (not to mention portraying opponents as weak on security).

As the Ausgrid decision shows, the continuing elevation of national security transfers yet more power and influence to security agencies, who themselves operate outside the normal parliamentary and media scrutiny to which other public sector agencies are subject. Security agencies, in consultation with their US counterparts, now get to dictate major foreign investment decisions. These are the same security agencies that gave us the Weapons of Mass Destruction excuse for invading Iraq; that bugged the East Timorese cabinet and continue, to the indifference of the media, to hound Witness K, who revealed it; that infuriated the Indonesian elite by bugging Susilo Bambang Yudhoyono and his family; that ignored the threat posed by Man Haron Monis in the lead-up to the Sydney siege. They deserve no more deference or trust than any other public servants.