So ASIO says that five of the unfortunates from the Oceanic Viking constitute a threat to national security.

What have they done? ASIO won’t say. What’s the evidence against them? It’s secret.

It beggars belief that, in the year 2010, ASIO can still behave like this.

After all, there’s plenty of past examples of ASIO’s handiwork available in the national archives: yellowing files permeated with arbitrary and capricious judgements by unaccountable people. For the most part, the dossiers are like student cookery: anything on hand simply got thrown in.

The historian Richard Hall notes in his account of ASIO during the Cold War, “the main thing ASIO men in the trade union area seemed to want was sexual gossip — who was sleeping with whom.” Thomas Shepherd, a former ASIO agent sent to compile information on figures such as  Jennie George and Marcia Langton and the various organisations of which they were members, makes almost exactly the same point: “[ASIO] were particularly interested in personal relationships. They wanted to know about who was getting off with whom, what kind of person everyone was. Were they stable or unstable, were they liars? Anything like that.”

Trivial, malicious tattle-tattle — but, once it got in the file, it stayed there, and impacted on people’s lives for years.

But you don’t need to delve into the distant past for examples.

Not so long ago, ASIO handed down one of its oracular pronouncements in respect of a certain Scott Parkin.  Parkin, you will recall, was an affable-seeming peace campaigner, whose previous brush with authority involved dressing as Tony the Tiger and distributing peanut butter sandwiches outside Haliburton’s offices.

On the basis of one of ASIO’s mysterious findings, his visa was cancelled, he was detained in solitary confinement and then deported. The Australian helpfully reported a mysterious source saying that Parkin planned to teach locals how to roll marbles under horses hooves — a claim that subsequently proved entirely untrue.

Because Parkin was American and white and an articulate English-speaker, his case received considerable attention (by contrast, Iraqi refugees Mohammed Sagar and Mohammad Faisal were detained on Nauru for years on the basis of security assessments, with almost no publicity whatsoever), and the ongoing court case has thrown a certain amount of light on ASIO’s methodology.

For instance, at the time, Phillip Ruddock assured the world that politics hadn’t entered the case, nor had the assessment been influenced by a foreign government.

We now know that was — what’s the word? — a lie, and that information from abroad (presumably the United States) did, in fact, shape the determination.

Now, one presumes that the adverse judgement about the Tamil refugees relates, in some way, to the Tamil Tigers. Given the Parkin case, it seems pertinent to wonder what role the Sri Lankan government has played in the current assessment. After all, it’s already been alleged that Sri Lankan officials have been allowed to question Tamils in Indonesia. That would be, mind you, representatives of the same Sri Lankan government leading an army caught on camera systematically shooting prisoners, a government with one of the worst human rights records in the world, and a documented tendency to regard all Tamils as terrorists; indeed, the same government whose persecution has led to the Tamils being officially declared refugees.

It is, of course, possible that the five individuals — even the little kids — are, in fact, exceedingly dangerous people. But in that case, why not make the information available so that the public can make up its own mind?

For that’s the other issue here. Immigration is a contentious political issue in Australia, an ongoing debate in the public sphere. Now, when Wilson Tuckey fantasised about terrorists sneaking themselves into the lucky country via leaky boats, it sounded barking mad. But now, as Joe Hockey gloatingly pointed out, ASIO has essentially made the same point — and, though the agency has provided no more evidence than Tuckey did, suddenly the argument is treated a thousand times more seriously.

How can this be healthy in a democratic country? Should a secret agency be playing such a  major role in a political debate, without even making its sources available?

“We’ll decide who comes to this country, and the circumstances under which they’ll come,” said John Howard.

Actually, that’s not true. ASIO will decide — and they won’t tell us why.