It would be improper to suggest politicians ought to set out detailed operational plans for security agencies. But it is reasonable to ask whether they have a view about the nature and scale of the threat and a response in resources and powers.

There have been several inquiries into the conduct of our security agencies across the past decade but none has stimulated the main parties to put down in writing their detailed, in-principle views on the effective management of secret investigations, the limits of the law in a free society or the relative priority of cyber-crime, Islamism or home-grown acts of organised violence.

Given that the controversial ASIO detention and interrogation powers will sunset during the next term of government it’s not unreasonable to ask at least which party will be prepared to let them expire. Similarly, given the present parliamentary inquiry into new powers we should at least know which party will or won’t acquiesce to ASIO’s request for mandatory meta-data retention by telecommunications companies.

It is difficult to criticise the work of our secret defenders. They are necessarily bound to keep secret many of the facts that would allay our concerns about their worth and success. But if we agree the threat of terrorism is serious enough to warrant the doubling of resources and new coercive powers ASIO received after the London 7/7 bombings, then it is serious enough that we should take an interest in its effective repulsion.

At the time of Willie Brigitte’s arrest our prime minister said that while he could not go into details about investigations on foot, the threats were “very, very significant”. Since these threats have not actualised it’s possible to argue the security agencies must have put all that new money and power to good use. They arguably have done a good job protecting us.

Sally Neighbour wrote a fascinating article in The Monthly in 2010 in which she quoted ASIO director David Irvine arguing: “There has been no major terrorist attack in Australia, but more Australians have been lost pro rata to terror attacks since September 11 than from most other Western countries. There have now been no less than four occasions when I believe a mass casualty attack within Australia has been avoided only because of the good work of intelligence and law enforcement authorities.”

It’s hard to argue with the man in the best position to know. But it’s also hard to shake the recollection of Homer Simpson’s satisfied boast to daughter Lisa: “Not a bear in sight. The Bear Patrol must be working like a charm.”

The challenge for both sides in defending their as yet unstated views on the ASIO powers is that we have a right as voters to know whether we have been safe because of good planning or good fortune.

More important, given the half-dozen reviews and reports that have occurred during the 9/11 decade, we deserve to know whether any improvements can be made.

Contrary to the implied consensus of silence emanating from both potential prime ministers, this is not a debate to be resolved simply by taking the advice of the security agencies themselves.

In tax, health, welfare and education we replace prime ministers so new policies have a chance to succeed where old ones have disappointed - not merely to provide the public service with a new spokesman.

Following the 9/11 attacks the US congress undertook a commission of review that found poor communication, territorialism and weak systems had undermined the performance of security agencies. The 2004 Flood report and the 2008 Street report found similar jealousies and weaknesses undermining performance here, with public safety unduly dependent on ad-hoc arrangements and personal relationships between senior agency staff.

The Clarke inquiry in 2008 into the arrest of Mohamed Haneef showed the improvements attempted after the earlier reports had not been entirely successful, with ASIO and the Australian Federal Police pointing fingers at each other after that case fell apart.

Almost a decade after the London bombings, the threat of a home-grown terrorist incident is still real. More than 20 people have been convicted of planning such attacks. But given the relative risk it poses against, say, car accidents, cancer, swimming pool drownings, bike helmet strangulations or shark attacks, we can afford the time to discuss this challenge with cool heads before agreeing to extend or increase the extraordinary powers granted to our security agencies.

The Parliamentary Joint Committee on Intelligence and Security has begun to examine potential enhancements to these powers. ASIO has requested that telecommunications companies be required by law to retain the personal account data of all customers in case they need to be accessed in the future. ASIO is correct that access to CAD information is not new. However, requiring private companies to keep records on their customers for no commercial reason but only for the sole purpose of reporting their activities to government would be.

“Agencies are seeking greater certainty that the information needed to protect the community will be there when they need it.”

This suggests all kinds of information that isn’t stored for the benefit of spies may be subject to future requests. It bears wondering what precedent this would set. Should your grocery bills be retained to see if you purchase too much fertiliser? Should your electricity company monitor your power use? Should your public transport card be monitored so the information is “there when they need it”?

ASIO says: “The reform proposals are about properly equipping our law enforcement, security and intelligence professionals to do the job that Australians have entrusted to them.”

It’s understandable they ask for more. It’s their job to catch the bad guys. But it’s our leaders’ job to balance that task with protection of the liberties we fight to preserve against invading ideologies and their agents.