Like the World War One 9.2-inch siege howitzer, Dennis Richardson has been a mobile weapon, deployed across many fields of battle, able to deliver a lot of ordnance with maximum elevation in a single shot.

The siege howitzer, a counter-battery artillery piece, fired a high-explosive shell weighing 290 lbs (130 kg). A Dennis diatribe also detonated with devastating effect.

Richardson retires next week after 48 years in the public service. Malcolm Turnbull describes it as ‘a long and distinguished career’, making ‘a significant contribution to Australia’s national security and foreign policy’.

The record glitters: Secretary of Defence (2012–16), Secretary of Foreign Affairs and Trade (2010–2012), Australia’s US Ambassador (2005–10), Director-General of ASIO (1996–2005), and Chief of Staff to Prime Minister Bob Hawke (1990–91).

Richardson is a well-rounded public servant, entering Foreign Affairs as part of the famous 1969 intake of diplomatic cadets. Unlike the other ’69-ers, Richardson didn’t define himself with a ‘DFAT’ persona, leaving in 1986 to join the Immigration Department because he saw it as a fascinating part of the bureaucracy, and then later the Prime Minister’s Department.

Soon after he was appointed to run Defence, I wrote a couple of columns noting that Richardson had joined Arthur Tange as the only public servant to have headed both Defence and Foreign Affairs. A great judge of Canberra big beasts, Philip Flood, commented that Tange is one of the three top public servants of the 20th century, while Richardson is one of the three top public servants of recent decades. Another fine judge, Max Moore-Wilton, said Tange was an old-school elitist while Richardson exemplifies the modern mandarin, willing to carry out a minister’s decision even if he’d argued vehemently against it.

Richardson could channel one important bit of the Tange mentality: in both Foreign and Defence, he served at his own pleasure as well as the PM’s pleasure. The big axe that now hangs permanently above the head of every Secretary in Canberra held no real threat for Richardson in his final decade at the top.

In Defence, Richardson said his goal was a ‘very strong philosophy to make Defence more of a unitary state rather than a federation, and a loose federation at that’.

The Defence Secretary obviously looms large, not least because of considerable statutory powers, especially over money. Yet even Richardson would admit that the military side of the Defence diarchy has a standing with ministers that he couldn’t match. It’s more than just the mystique of the slouch hat. Politicians have changed the power settings—the relative clout of the Secretary has declined considerably from the highpoint achieved by Tange. Any Defence Secretary’s ability to faze or out-face the minister has declined as sharply as his ability to dominate the military leadership.

The Richardson style was on full display when he fronted Senate Estimates. He was correct and cordial, always direct, never deferential. Senators got what Richardson wanted to give ‘em—usually with plenty of detail.

Another style note, to file under dress code and power costumes. Richardson embraced a fashion which only arrived in Canberra’s top ranks this decade—wearing a suit without a tie. The tieless look is the biggest fashion shift for Canberra blokes since Paul Keating made the double-breasted jacket the power uniform of choice. Plenty of white-shirt-with-tie-Secretaries still abound, but Dennis dispensing with the tie is a style message that mattered—especially amid the tribal hierarchies of Defence.

Richardson’s public service philosophy is set out in this speech he gave to the Institute of Public Affairs. These are the key points:

• In a crisis, you always go to it, never stand back. Always head for the source of the trouble, don’t skirt the edges.
• Confront the immediate crisis; then have the discipline to deal with the next issue and give it complete focus without being distracted by what went before.
• Create an environment where people feel able to raise the most sensitive things with you.
• Overcome the temptation to assume that you can regulate your way to perfection. More often than not when things go wrong, it’s a result of human error rather than systemic failure.

Defence will miss the dynamism, not the Dennis diatribes. Senior Defence types tried to ‘do’ Dennis in strength, or at least enter his office in pairs, to lay down covering fire and have the numbers to carry away the wounded.

A Richardson overview—the geostrategic bones of the 2016 White Paper in a quick read—is his 2015 Blamey Oration. The US–China is the central relationship: how does Australia position itself when it’s ‘friends with both, allies with one’? And there’s a classic, dry Richardson barb directed at China’s South China Sea sand castle creation: ‘The speed and scale of China’s land reclamation on disputed reefs and other features does raise the question of intent and purpose; it is legitimate to ask the purpose of the land reclamation—tourism appears unlikely.’

For a Richardson summation as he leaves, here’s his speech in March to APSI’s State of the Region Masterclass, arguing that one of many things Donald Trump will demand is that Australians who believe in the ‘importance and benefits of the alliance’ are going to have to work harder.

In retirement Dennis Richardson will devote himself to argument, wine, his beloved Canberra Raiders and being Patron of the RSPCA. The Raiders and the RSPCA give you two Richardson dimensions as a mandarin with Oz characteristics: the love of (sporting) excellence and the feel for the underdog.