Retribution for political crimes is often a long time coming. We’ve all seen film of geriatric ex-Nazis being finally brought to justice for crimes committed 50 or 60 years earlier; accounts that demand to be settled, whatever the cost.

A lesser version of the same phenomenon was played out this morning, when 90-year-old former prime minister Gough Whitlam testified at the inquest into the murder of Brian Peters, one of five Australian-based journalists killed in Balibo, East Timor, more than 31 years ago.

Whitlam said, as he has always maintained, that he was unaware of the deaths until several days afterwards. That conflicts with other accounts the inquest has heard, but at this distance it is virtually impossible to say who is telling the truth. Memories fade, motives blur, evidence disappears.

The inquest is limited in scope: it can only inquire into the causes of death, not into any subsequent cover-up. Even now, although he and his colleagues have been asked to testify, Whitlam’s government is not on trial.

But that is how government works. Its upper echelons are shrouded in secrecy, described as “national security”, “executive privilege”, “commercial-in-confidence”, or whatever.

Cabinet papers are embargoed for 30 years, intelligence material even longer, and teams of government lawyers wait to ambush anyone who releases sensitive (read: politically embarrassing) material any sooner. Parliamentary inquiries, which could pierce the veil, are usually cowed into impotence.

Most senior decision-makers in any government are over 50, often well over. That means that 30 years later they are quite likely to be either dead or senile. It’s too late for any useful investigation to be launched; the trail has gone cold.

When the cabinet papers from the “children overboard” affair are released, for example, John Howard, if he’s still alive, will be 92. How likely is it that he will be put in the witness box then, or that he will have anything sensible to say if he is.

It’s important to try to find out what really happened in Balibo. But it’s even more important to let the light of publicity into the workings of government, because that might help to prevent such crimes in the future.