Will no one rid me of this meddlesome priest? asked Henry II as he instigated the murder of the Archbishop of Canterbury, Thomas Becket, in 1170. Down through the ages, presidents and princes around the world have been murderers and accessories to murder, as the great Harvard sociologist Pitirim Sorokin and Walter Lunden documented in statistical detail in their master workPower and Morality.

_One of theirmain findingswas that the behavior of ruling groups tends to be more criminal and amoral than that of the people over whom they rule.

_

What rulers crave most is deniability. But with the murder of Saudi journalist Jamal Khashoggi by his own government, the poisoning of former Russian spies living in the United Kingdom, and whispers that the head of Interpol, Meng Hongwei, may have been executed in China, the curtain has been slipping more than usual of late. In Riyadh, Moscow, and even Beijing, the political class is scrambling to cover up its lethal ways.

But no one should feel self-righteous here. American presidents have a long history of murder, something unlikely to trouble the current incumbent, Donald Trump, whose favorite predecessor, Andrew Jackson, was acold-blooded murderer, slave owner, and ethnic cleanser of native Americans.

For Harry Truman, theatomic bombing of Hiroshimaspared him the likely high cost of invading Japan. But the second atomic bombing, of Nagasaki, was utterly indefensible and took place through sheer bureaucratic momentum: The bombing apparently occurredwithout Trumans explicit order.

Since 1947, the deniability of presidential murder has been facilitated by the CIA, which has served as a secret army (and sometime death squad) for American presidents

Since 1947, the deniability of presidential murder has been facilitated by the Central Intelligence Agency, which has served as a secret army (and sometime death squad) for American presidents. The CIA has been aparty to murders and mayhemin all parts of the world, with almost no oversight or accountability for itscountless assassinations. It is possible, though not definitively proved, that the CIA evenassassinated UN secretary general Dag Hammarskjld.

The CIA has only been held to public account on one occasion: the 1975 US Senate hearings led by Frank Church. Since then, the CIA has continued its violent and, yes, murderous ways, without any accountability for it or for the presidents who authorized its actions.

Many mass killings by US presidents have involved the conventional military. Lyndon Johnson escalated US military intervention in Vietnam on the pretext of a North Vietnamese attack in the Gulf of Tonkin that never happened. Richard Nixon went further: By carpet-bombing Vietnam, Cambodia and Laos, he sought to instill in the Soviet Union the fear that he was an irrational leader capable of anything. (Nixons willingness to implement his madman theory is perhaps the self-fulfilling proof of his madness.)

In the end, the Johnson-Nixon American war in Indochina cost millions of innocent lives. There was never a true accounting, and perhaps the opposite:plenty of precedents for later mass killings by US forces.

The mass killings in Iraq under George W Bush are of course better known, because the US-led war there was made for TV. A supposedly civilized country engaged in shock and awe to overthrow another countrys government on utterly false pretenses.Hundreds of thousands of Iraqi civilians diedas a result.

Barack Obama was widely attacked by the right for being too soft, yet he too notched up quite a death toll. His administration repeatedlyapproved drone attacksthat killed not only terrorists, but also innocents and US citizens who opposed Americas bloody wars in Muslim countries.

He signed thepresidential finding authorizing the CIA to cooperate with Saudi Arabiain overthrowing the Syrian government. That covert operation (hardly discussed in the polite pages of The New York Times) led to an ongoing civil war that has resulted in hundreds of thousands of civilian deaths and millions displaced from their homes.

He used North Atlantic Treaty Organization air strikes to overthrow Libyas MuammarGaddafi, resulting in a failed state and ongoing violence.

Under Trump, the US has abetted Saudi Arabias mass murder (including of children) in Yemen by selling it bombs and advanced weapons with almost no awareness, oversight, or accountability by Congress or the American public. Murder committed out of view of the media is almost no longer murder at all.

When the curtain slips, as with the Khashoggi killing, we briefly see the world as it is. A Washington Post columnist is lured to a brutal death and dismembered by Americas close ally.

The American-Israeli-Saudi big lie that Iran is at the center of global terrorism, a claimrefuted by the data, is briefly threatened by the embarrassing disclosure of Khashoggis grisly end. Crown Prince Mohammad bin Salman, who ostensibly ordered the operation, is put in charge of the investigation of the case; the Saudis duly cashier a few senior officials; and Trump, a master of non-stop lies, parrots official Saudi tall tales about a rogue operation.

A few government and business leaders have postponed visits to Saudi Arabia. The list of announced withdrawals from a glitzy investment conference is awhos who of Americas military-industrial complex: top Wall Street bankers, CEOs of major media companies, and senior officials of military contractors, such as Airbuss defense chief.

The US prides itself on being a constitutional democracy, yet when it comes to foreign policy, the president is little different from a despot. Trump has just announced theUS withdrawal from the Intermediate-Range Nuclear Force Treatywithout so much as a mention to Congress.

Political scientists should test the following hypothesis: Countries led by presidents (as in the US) and non-constitutional monarchs (as in Saudi Arabia), rather than by parliaments and prime ministers, are especially vulnerable to murderous politics. Parliaments provide no guarantees of restraint, but one-man rule in foreign policy, as in the US and Saudi Arabia, almost guarantees massive bloodletting.

Americans are rightly horrified by Khashoggis murder. But their own governments murderous ways may be little different. The pervasiveness of state-sponsored killings is no excuse for treating murder as acceptable, ever. It is instead a rationale for subjecting power to strict constitutional constraints and especially to international law, including the United Nations Charter and the Universal Declaration of Human Rights.

This is our only true hope for survival and safety in a world where the casual resort to violence can easily be the end of all of us.

Professor Sachs is a distinguished commentator and formerly Director of the Eath Institute y at Columbia University.