The Iraq war is the first exhibit, but it is not the most extreme. In August 2002, frustrated that talk of a diplomatic solution was threatening to intrude on his personal timetable for the invasion of Baghdad, Cheney decided to push US policy into a more aggressive phase. George Bush had said that Saddam Hussein "desires" weapons of mass destruction. Cheney took it further. "There is no doubt that Saddam Hussein now has weapons of mass destruction; there is no doubt that he is massing them to use against our friends, against our allies and against us," he said in a speech to the Veterans of Foreign Wars. It was "as great a threat as can be imagined".

The speech was tantamount to a declaration of war and we know from Bob Woodward's book Plan of Attack that Colin Powell, Bush's then secretary of state, was "astonished". Powell said Cheney seemed to be in a "fever" for war. His martial ambition for his country sat uncomfortably on a man who had none for himself. With the US at war in Vietnam, the young Cheney, of drafting age, applied for four deferments to avoid service. "I had other priorities in the '60s than military service," he would say later. This is why he has been branded in the US as one of the Administration's so-called "chicken hawks". And yet Cheney has the hide, during his visit to Sydney, to schedule an event at Victoria Barracks where he will pose with Aussie war veterans, hoping, one presumes, for valour by association.

The Bush Administration's policy of obtaining information "under duress" from detainees in US facilities abroad, a practice otherwise known as torture, is another Cheney accomplishment. Powell's former chief of staff, the retired army colonel Larry Wilkerson, told CNN in November 2005, during a discussion of torture policy: "There's no question in my mind where the philosophical guidance and the flexibility in order to do so originated." In the office of the Vice-President of the United States.

Where the war dismayed the peoples of the world, including many pro-American ones, the torture policy disgusted them. This Vice-President has betrayed the high idealism that the US, at its best, has long offered the world. "How can America go around the world preaching democracy and human rights with a straight face while you have the Vice-President in Washington defending torture?" asks Jim Steinberg, the dean of international relations at the University of Texas and a former deputy national security adviser in the Clinton administration. So it may come as no surprise that Cheney, who vanishes to "an undisclosed location" in times of danger and whose only notable act of personal derring-do was to shoot his friend during a hunting expedition, is not terribly popular in today's America. A Harris poll this month put his approval rating at 29 per cent, his all-time low in the Harris series, making him several points more unpopular than the President.

John Howard will embrace the Vice-President today and tomorrow, but could he really want to be seen in close company with this man at this moment as Kevin Rudd brings his Iraq policy under fresh scrutiny? Even old Republican friends of Cheney have disavowed him for his fevered embrace of the neo-conservative agenda of imposing democracy at the point of a gun. The national security adviser to two Republican presidents, Brent Scowcroft, one of the wise old men of US foreign policy, told The New Yorker magazine: "I consider Cheney a good friend. I've known him for 30 years. But Dick Cheney I don't know any more."

Still, despite the political liability that Cheney has become, Howard can use the opportunity to reassert his title as the custodian of the US alliance, always a positive in the eyes of Australian voters. Cheney may be in Australia to say thanks, but he is also here because he has a lot less to do in Washington these days. The Democratic Party's victory in the congressional elections brought a clear end to the power of the neocon agenda in US politics. The firing of Donald Rumsfeld, one of Cheney's greatest allies in the Administration, was the clearest public indication that the neocon era was over. And look what has happened since. Last week the North Koreans agreed to suspend their nuclear weapons program. It was a deal the former Bush neocon John Bolton said that the US State Department had wanted to do six years earlier.

Why hadn't it? In part because Cheney vetoed it. Cheney has always believed that the US should never make any up-front concessions in any negotiation. Speaking of Cheney and Rumsfeld, the former US deputy secretary of state Richard Armitage had said: "Their idea of diplomacy is to say, 'Look f---er, you do what we want."' But the marginalisation of the neocon project has meant that Cheney's influence has been reduced, as The Washington Post pointed out this week. And so the deal was allowed to be done.

The US has moved into the post-neocon phase, and the fact that Cheney is here for the first time in six years, to say "thanks", is a sign that he doesn't have more important things to do in DC in his reduced status. And, however unloved he may be here, Americans are in no great rush to welcome him home again. Walter Russell Mead, the Henry Kissinger fellow at the Council on Foreign Relations in New York, yesterday made this generous offer: "We are willing to let you have him for as long as you like." Peter Hartcher is the Herald's political editor.