Leader of the Opposition? No, although that post certainly is a stinker - just ask Bill Shorten.

The position in question is the most senior rank of the Australian Federal Police.

Australia's "top cop" Andrew Colvin announced this week that he will hand in his badge and gun after a taxing five year stint.

Colvin's grim yet procedurally reassuring presence had become a familiar one in the era of the home-grown enemy, this age of treason.

The short-sleeved commissioner has been wheeled out to explain the latest terror plot diligently foiled or to help justify the widening powers sought by police and the courts.

Not anymore. Colvin leaves at an uneasy time for the nation, and at a surprisingly tricky time for the AFP, which faces acute morale problems and mounting external critics.

A 2018 Essential survey of public attitudes found that the "federal police" is the most trusted of all our national institutions, ahead of state police forces and above even the supreme judicial authority, the High Court of Australia.

Its success in detecting fanatical conspiracies and frustrating their deranged plans to cause carnage is a big part of that respect.

But so too has been the AFP's record of addressing internal corruption, staying out of the hyperbole game, and generally flying above the political ruck as well.

Mostly, anyway.

It was hardly the AFP's fault that Tony Abbott used its headquarters to call on Australian Muslims to muscle up.

"I've often heard Western leaders describe Islam as a 'religion of peace'. I wish more Muslim leaders would say that more often, and mean it," the embattled PM needled during an eyebrow-raising speech on national security in February 2015.

Abbott's more vigorous can-kicking on the "Muslim" question, came just weeks after surviving one of the more farcical episodes in Australian politics, the infamous "empty chair challenge" in which 60 per cent of his backbench voted against him despite no other candidate running.

A critically wounded Abbott was desperate to shift the focus elsewhere.

And where better than national security, the "go-to" in times of governmental "emergency".

Senior AFP officers were privately appalled, aware that their best chances of forestalling Islamist extremists came from maintaining high levels of trust and inclusion with Muslim community leaders and their broader communities.

Australians can be grateful for the AFP's success in these endeavours.

Yet you only get so much credit for causing things to not happen.

It is a truism but the AFP and partner agencies ASIO and the state police services need to be perfect every time, whereas groups intent on mass casualties have only to get lucky once.

So it is not hard to see why Colvin might feel that he has dwelled long enough in the Rumsfeldian darkness of known unknowns and worse.

But of course, with greater power comes greater responsibility and strong public support is never a given.

The AFP's officious black-letter pursuit of whistle-blowers and journalists using raids on a reporter's home and the ABC has brought overdue attention on dwindling press freedoms, and on the punitive pursuit of officials who have acted in the national interest, in good conscience, and as a matter of last resort.

Moreover, the raids, which came within two days of each other and just after the federal election, have hung a lantern over the political leanings of the agencies themselves, while inviting a re-consideration of powers invariably justified against the ubiquitous terrorist threat.

Colvin's notice coincided with revelations the AFP had sought the finger and palm prints of two ABC reporters several weeks before the raids occurred.

This gave the lie to post-raid assurances from Attorney-General Christian Porter that journalists were never the object of these investigations, and that charges were not in consideration.

This new information shreds that. In any event, Porter has since admitted he had not been privy to the AFP's intentions.

Porter's distance from the AFP is a function of its relocation under the mega-security portfolio's umbrella of Home Affairs - a move that Colvin is said to have found frustrating.

But then, perhaps the Attorney-General is too stretched to worry about inner-city pre-occupations like a free press.

After all, he has the urgent task of drawing up a legislative solution to a febrile religious discrimination debate that barely exists beyond conservative politics.