In early May this year, two Dutch men reported a murder to their local police station in the city of Tilburg.

"There is a murderer who has admitted the deed on television and who dumped the evidence at sea," one of the men apparently said.

The "murder" in question referred to the killing of Osama bin Laden by US Navy Seals. By all accounts the Dutch men's actions in going to the police were not at all tongue-in-cheek, but completely serious.

Beneath the outrage of the civic-minded pair, whose exploits were cited in a House of Commons report into the legality of the bin Laden killing, lies a very troubling issue. A crime had been committed and, as one of the Dutch men bemoaned, "the whole world is celebrating".

Bin Laden's was just the first of a number of high-profile extrajudicial killings which, taken together, are pointing to a very disturbing trend in the development of international justice.

That is, the replacement of war crimes trials, and other traditional forms of justice as we used to understand them in the West, by summary executions, which go barely remarked upon by the world's leaders.

In September a suspected al Qaeda member, Anwar al-Awlaki, an American citizen, was killed in a CIA drone strike in Yemen.

Then last month, the Libyan dictator, Muammar Gaddafi, was summarily executed by Libyan rebels.

The Guardian reported that Gaddafi was shot in the head 20 minutes after his capture; footage taken on his captors' camera phones included "images of a wounded Gaddafi being sodomised with what looked like a bayonet".

The response by Australia's Minister for Foreign Affairs, Kevin Rudd, to Gaddafi's killing was typical of the new attitude of leaders of the world's liberal democracies to such events.

"This is an historic day for the people of Libya, for the people of the wider Arab world, and the world at large and people who love freedom," Rudd said.

Not a word about the way Gaddafi met his fate; not a pause to contemplate whether justice wouldn't have been better served by hauling the tyrant before a war crimes tribunal.

The day of reckoning for all these unsavoury characters - bin Laden, Awlaki, and Gaddafi- was always coming. And the world is undoubtedly a better place without their like. But since when did things like evidence, witnesses, judges and trials become so passé´?

That's a question Australia's leaders should be putting to the United States President, Barack Obama, when he visits these shores in a little over a week.

The Obama administration has presided over a dramatic increase in the number of "targeted killings" being carried out by the CIA, often in conjunction with the Department of Defence, in nations the US is not at war with, such as Pakistan and Yemen.

In doing so it is setting a very dangerous precedent for other countries and the future dispensation of international justice. It's a precedent for which we are all, by our collective failure to question what Obama is doing - particularly the US's allies - culpable.

As Christof Heyns, the United Nations special rapporteur on extrajudicial, summary or arbitrary executions, warned after the killing of Awlaki: "The use of such methods by some states to eliminate opponents in countries around the world raises the question why other states should not engage in the same practices ... The danger is one of a global war without borders, in which no one is safe."

The US President, a constitutional lawyer, has proven extremely reluctant to explain to Americans why it is suddenly OK for America to kill, without trial, without accountability, its own citizens.

The New York Times reported last month on the contents of the secret legal memorandum that purports to provide the legal basis for Obama's order to kill American citizens by drone strike.

Obama has refused to release the memo, but it supposedly says that despite an executive order banning assassinations, despite a federal law against Americans murdering other Americans abroad, despite protections in the US Bill of Rights, and despite international law, killing the New Mexico-born Awlaki was lawful so long as "it were not feasible to take him alive".

The drone strike that killed Awlaki, accused of involvement in various terrorist plots, also killed another US citizen, Samir Khan. Khan produced al-Qaeda propaganda, but was not on the CIA's list of "kill" targets. His death has been described as collateral damage. A separate CIA drone strike also killed Awlaki's teenage son.

Philip Alston, the former UN official in charge of investigating extrajudicial executions, has written that assertions by Obama administration officials that its targeted killings comply with international standards are undermined by the complete lack of transparency or accountability over what they are doing. We don't know, for instance, on what basis the CIA chooses its targets, or how many people it has killed.

Or as The Economist wrote of these killings, "more information is needed". It asked, "is the President's right to place an individual on a 'kill or capture list' greater than the individual's constitutional right to due process? The Supreme Court should look at this rapidly."

The Australian Defence Force is reported to be involved in drone-based killings in Afghanistan. As a close military partner and ally of the US, are we asking the hard questions about its wider program of targeted assassinations? Are we thinking about what impact these developments are having on the fabric of international justice?

You can bet, if Rudd's ill-judged response to Gaddafi's killing was anything to go by, this topic won't be on the agenda for bilateral talks during Obama's visit.

And that will suit Obama just fine.

Murders no one wants to talk about