CANBERRA –

As in other aspects of human life, the march of military technology has greatly outpaced the laws and institutions to regulate the behavior they make possible. The Obama administration has so greatly expanded the Bush policy of drone strikes as to leave neutral observers queasy about the legal regime governing the new tools of warfare.

Last October, Pakistani tribal elders from North Waziristan traveled to Islamabad to protest against the U.S. drone strikes. With them was a 16-year old boy named Tariq Khan. He did not want to return home for fear of the drones. He did and died in a drone attack four days after the Islamabad jirga (tribal assembly).

In September 2011, Anwar al-Awlaki, an American of Yemeni descent, was killed by a U.S. drone strike somewhere in Yemen. His 16-year old son (that is, a juvenile) was killed in a followup strike some weeks later.

These terrifying unseen killers that strike silently from the sky are a potent, unnerving symbol of unchecked and potentially cruel and capricious American power. Independent estimates suggest that between 2,000 and 3,000 people have been killed in such U.S. strikes in the last eight years, around 80 percent during the Obama administration. Washington columnist Aaron David Miller concluded that "as shown through his stepped-up drone campaign, Barack Obama has become George W. Bush on steroids."

Three-quarters are claimed to be militants. Others claim that drone strikes kill seven times as many followers as top-level terrorists. An Alice in Wonderland definition eases legal and moral concerns. The administration counts all military-age males in a drone strike zone as combatants unless they are clearly proven — posthumously — to have been innocent. This is certainly convenient in claiming minimum loss of innocent civilian lives.

Given the memorable record of the U.S. intelligence on the "slam dunk" evidence proving Iraq President Saddam Hussein's weapons of mass destruction, the secretive determinations of guilt and imposition of capital punishment by intelligence-bureaucratic processes instead of open and contested judicial trials is troubling.

Having criticized the Bush administration for the secret practices of surveillance, interrogation and detention, Obama has dramatically expanded the practice of secretly putting people on kill lists. Drone warfare greatly stretches the boundaries of the imperial presidency relative to Congressional checks and judicial oversight.

It also raises the question: Is the extrajudicial of killing foreigners (and Americans living abroad) following a bureaucratic determination, as Obama is doing, more or less frightening and morally reprehensible than capturing them and sending them to detention and torture in Guantanamo Bay, as Bush did and Obama condemned?

The policy is justified on grounds of neutralizing imminent threats. In a speech on March 5, Attorney General Eric Holder explained that "an 'imminent threat' incorporates considerations of the relevant window of opportunity to act, the possible harm that missing the window would cause to civilians, and the likelihood of heading off future disastrous attacks against the United States."

Because of al-Qaida's proven ability and willingness to attack with little or no notice and cause devastating casualties, he added, the president is not required "to delay action until some theoretical end-stage of planning — when the precise time, place, and manner of an attack become clear. Such a requirement would create an unacceptably high risk that our efforts would fail, and that Americans would be killed."

This is not a definition of "imminent" that most scholars of international law would recognize. Holder did not address some fundamental questions: How is a threat determined, what counts as decisive evidence on determining the status of operational commander, and how do officials conclude that arrest is not feasible?

The growing drone dependency owes to its convenience: It is faster, less complicated and more expedient to eliminate the enemy terrorist than to arrest and try him. It also eliminates the risk to U.S. soldiers.

But convenience is not enough to justify remote-controlled war in law and international humanitarian law (IHL). U.N. Special Rapporteur Philip Alston argues that extrajudicial killings using weapons like drones pose a challenge to international law and may constitute war crimes as intelligence agencies "do not generally operate within a framework that places appropriate emphasis upon ensuring compliance" with IHL.

Moreover, "because operators are based thousands of miles away from the battlefield, and undertake operations entirely through computer screens and remote audio-feed," they risk developing "a 'Playstation mentality' to killing." In the aftermath of the terrorist attacks of Sept. 11, 2001, adherence to human rights law, the laws of war and IHL had softened. "The result has been the displacement of clear legal standards with a vaguely defined license to kill, and the creation of a major accountability vacuum."

In sum, there is both a legal and a strategic problem with the increasing use of drones to kill the enemy:

• Justice dispensed by drones cannot be reconciled with the rule of law.

• Sir Sherard Cowper-Coles, Britain's former special representative to Afghanistan and Pakistan, insists that drone attacks are counterproductive because of the hatred they generate.

In a now-famous memo on the war on terror (Oct. 16, 2003), U.S. Defense Secretary Donald Rumsfeld posed the prophetic and critical question: "Are we capturing, killing or deterring and dissuading more terrorists every day than the madrassas and the radical clerics are recruiting, training and deploying against us?"

What he did not ask was the cause-and-effect link between U.S. successes in capturing, torturing and killing terrorist suspects, and more terrorists being recruited in consequence. It was in this sense that Sir Ivor Roberts, the British ambassador to Italy, remarked to the annual meeting of British and Italian political leaders in Rome on Sept. 19, 2004, that al-Qaida had cause to celebrate the re-election of President George W. Bush. For "Bush is al-Qaida's best recruiting sergeant."

Thus it was that Pakistani Faisal Shahzad, the failed Times Square bomber of May 2010, when asked about potential innocent victims of his plot, replied: "U.S. drone strikes don't see children, they don't see anybody. They kill women, children; they kill everybody."

Ramesh Thakur is a professor at the Crawford School of Public Policy, Australian National University, and an adjunct professor at the Institute of Ethics, Governance and Law, Griffith University.