After landing in Sydney airport following a flight from Brisbane, Australia’s most decorated living soldier, Ben Roberts-Smith, was arrested by Australian Federal Police.

He’s faced court in New South Wales and been charged with five counts of the war crime of murder, following a years-long joint investigation between police and the Office of the Special Investigator.

Roberts-Smith is only the second Australian to be charged with such offences, and the most high-profile.

But the path to this point has been long and winding. Here’s how we got here, and what happens next.

The media reporting and defamation case

This is not the first time Roberts-Smith will face a court for alleged war crimes.

In 2018, he sued three journalists and Fairfax Media for defamation. This followed media reports by Australian journalists Nick McKenzie, Chris Masters and David Wroe, alleging he had murdered Afghani personnel during operations in Afghanistan.

Roberts-Smith has always denied any wrongdoing.

To defend themselves, the journalists relied on proving in court that their reporting was accurate: that Roberts-Smith had, in fact, committed war crimes.

In 2023, the court held there was sufficient evidence that Roberts-Smith had himself murdered two Afghani personnel and ordered or pressured a subordinate soldier to murder another.

Because that trial was a civil proceeding, lawyers representing the journalists did not need to prove the allegations beyond a reasonable doubt. They only needed to meet the lesser standard of proof that the allegations were true on the balance of probabilities.

In a criminal court, where Roberts-Smith will answer a case brought by the AFP, the court will need to be satisfied beyond reasonable doubt to convict him of the charges.

The maximum penalty for the war crime of murder is life imprisonment.

The defence inquiry

The allegations against Roberts-Smith are part of a much larger investigation process.

In 2016, the Australian military began investigating allegations Australian soldiers has committed war crimes in Afghanistan. The Inspector-General of the Australian Defence Force tasked Paul Brereton with preparing a report on it.

Four years later in 2020, the so-called Brereton report was released publicly. It outlined 39 murders of civilians and prisoners by Australian soldiers.

The scale of the allegations was such that the Australian government created the Office of the Special Investigator. The office is to further investigate war crimes and recommend the prosecution of people involved.

Since the release of the report, progress has been slow, given there appeared to be considerable evidence of wrongdoing.

In 2023, Oliver Schulz was arrested and charged with the killing of an Afghani civilian. Evidence of this accusation was first made public in 2020. He pleaded not guilty and his case goes to trial next year.

Why has it taken this long?

As the Roberts-Smith story played out in civilian court, public commentary began to include speculation over the likelihood of future criminal charges against him.

But Australian authorities bringing Australians to trial for war crimes is uncommon. Though Australia has prosecuted alleged war criminals of foreign nationals in the past, Schulz and Roberts-Smith are the only two Australians to be both arrested and charged.

Investigating war crimes is challenging work at the best of times. In Roberts-Smith’s case, the Office of the Special Investigator’s director of investigations, Ross Barnett, said the political situation in Afghanistan has made the work even harder. Australian boots on the ground were effectively barred.

Beyond practical considerations, it’s likely the prominence of Roberts-Smith as both a decorated soldier and celebrity has made investigators particularly cautious. A failed trial would likely weaken public trust in the entire investigation and prosecution program.

Many Australians celebrate the service of the country’s military personnel. They would expect charges against former soldiers for acts committed during their service would be carefully considered.

What are the laws at play?

Australian authorities legally had no choice but to undertake the costly, fraught and lengthy process of pursuing war crimes allegations.

In 2002, the Australian government joined the International Criminal Court. Membership requires parties to domestically legislate war crimes law.

It also requires governments to investigate, and where appropriate, prosecute, those who are alleged to have committed war crimes.

If a government is unwilling, or unable, to investigate and prosecute war crimes allegations, the International Criminal Court has the power to carry out the task instead.

In this case, Australian authorities did investigate the allegations and it is because of the work of the Office of the Special Investigator and the Australian Federal Police that Roberts-Smith will face trial in Australia, not overseas.

Due to the seriousness of the alleged crimes, Roberts-Smith will most likely be tried in a state supreme court, as is the case with Schulz.

Procedurally, the trial will unfold like any other criminal trial. Though the crimes are international and entwined with Australia’s membership of the International Criminal Court, war crimes and Australia’s international legal obligations in this space have subsequently been adopted into Australian criminal law.

Australia on the international stage

The decision to prosecute Roberts-Smith is at the same time both expected and in someways surprising.

On the one hand, it seemed highly likely he would be charged after his failed defamation case. The judgment set out in particularly clear detail three instances of Roberts-Smith murdering, or ordering the murder of, Afghani personnel.

Though the burden of proof was lower, it seemed clear that Roberts-Smith would eventually face criminal prosecution.

On the other hand, war crimes law seems to be at a serious crossroads internationally. In conflicts unfolding across the globe, governments – including allies of Australia – have shown what seems to be a growing disregard for war crimes law.

The upcoming prosecution of Australia’s most highly decorated soldier, who acted as the public face of the Australian military for so long, demonstrates a surprising commitment to international law that is increasingly out of step with some of the country’s major partners.