Andrew Gumbel: Is this the most dangerous man in the world?

The last time the wider world was quite this appalled by the actions and policy agenda of a new American president, international relations were buried deep in the Manichean logic of the Cold War, the postwar consensus on the welfare state was about to blow apart and market-driven greed, that defining characteristic of the Eighties, was well on its way to being considered good.

The new president then was, of course, Ronald Reagan, a man who unveiled himself to the world by denouncing the Soviet Union as an "evil empire", laboured under the misconception that nuclear missiles could be recalled once they had been launched, and cracked jokes into open microphones that "the bombing begins in five minutes".

Reagan looked like terrible news all round. He bumbled. He couldn't get his facts straight. He was virulently anti-communist. He was so in thrall to the religious right that his secretary of the interior, James Watt, argued in public that there was nothing wrong with ravaging the environment since the end of the world was nigh anyway.

And yet things didn't work out quite as badly as some people feared. Granted, Reagan sponsored a succession of bloody wars in central America, pounded Libya and Grenada, propped up violent and corrupt dictatorships across the Third World, and ratcheted up military spending so far that it created massive deficits and knocked the world financial system for a loop, largely to the detriment of developing countries.

But at least he didn't blow us all up. In fact, he and Mikhail Gorbachev came within a hair of agreeing on the destruction of whole classes of nuclear weapons in Reykjavik in 1985 and created sufficient détente between East and West that, when the communist regimes of eastern Europe collapsed a year after Reagan left office, they did so peacefully.

Now comes the new bogeyman, in the form of George W Bush. To the protesters massing outside the G8 summit in Genoa this weekend, as well as quite a few commentators in European capitals, the new President is as bad as Reagan, and possibly even worse. He has been in office barely six months, and already wants to rip up the landmark Anti-Ballistic Missile Treaty – the cornerstone of all arms-control negotiations during the Cold War and since – so that he can build the "star wars" defensive missile shield that Reagan flirted with and ultimately rejected. And he has reneged on the United States' commitment to halt global warming by rejecting the 1997 Kyoto Protocol on emissions reduction.

With his dogged "America first" attitude and refusal even to broach discussion on the key planks of his foreign and security policy, he has antagonised just about every major player on the international stage – Russia, China, France and the rest of the European Union – as well as a number of smaller, potentially threatening countries such as North Korea. Like Reagan, Bush seems woefully underprepared for the rigours of high office. He, too, bumbles, and makes train-wrecks of the English language. He, too, owes much of his grassroots support to gun lobbyists, religious conservatives, polluting industries and defence contractors.

But, unlike Reagan, Bush can't claim to be acting on a popular mandate. In fact, there is still considerable argument over the legitimacy of his rise to power following last November's nail-biting presidential election and the 36-day recount battle in Florida that followed. Having waged a centrist campaign, the sharp veer to the right he has taken on every aspect of policy, from environmental protection to military spending, has struck many people, both inside America and outside, as a betrayal of the voters' trust.

There is a blitheness and arrogance about this new White House – another striking departure from the Reagan style – that has touched a particularly raw nerve. The Bush administration has ignored repeated warnings from scientists that a missile defence system can never work; yet the immense logistical and strategic problems are apparently no obstacle to pumping hundreds of billions of dollars into the pockets of defence contractors over the next several years.

There has been a similar reluctance to confront reality over global warming, with White House aides initially attempting to dismiss the whole phenomenon as scientific speculation until a report from the government's own National Academy of Sciences cut the ground out from under their feet.

Just how dangerous is George W Bush? Seen from the streets of Genoa, he certainly seems to represent a disconcerting step back in time towards nuclear proliferation, American isolationism and the slow destruction of the planet's natural resources by heavy industry. Seen from the United States, however, the picture is more nuanced. What is striking about the president is not the doggedness of his agenda but actually the opposite: his extraordinary disengagement from political life and his tendency to bend in the wind on issue after issue as though he has no confidence in his own mind.

This is a chief executive who is almost never in the Oval Office. If he is not giving speeches in the American heartland, he can be found at his Texas ranch, or playing golf in Kennebunkport, or at some other location far from the nexus of power. While the heavy lifting is left to the likes of Dick Cheney, his vice-president, and Karl Rove, his chief political adviser, Bush puts in short work days, takes naps, and frequently gives the impression of having forgotten he is President altogether.

Even in London on Friday, he visited the British Museum, Buckingham Palace and Winston Churchill's wartime Cabinet Rooms before he got down to any real work. Such disengagement often translates into lack of resolve.

Having initially questioned the scientific basis of global warming, Bush now says he wants to find an alternative to the Kyoto Protocol rather than ignore the issue altogether. Having said he wanted to block federal funding for research into embryonic stem-cells for reasons of conscience – the hot domestic topic du jour – he is now furiously seeking a compromise to placate an overwhelmingly favourable public and avoid a brain-drain of top scientists.

Bush is certainly no demagogue and that can be a good thing on international issues where seasoned advisers such as Colin Powell, the Secretary of State, can step in if things get hairy. Powell was the one who held the his boss's hand during the spy plane stand-off with China earlier this year. When it looked as though Bush was being overzealous in isolating North Korea around the same time, the man who made the ice-breaking call was none other than George Bush Sr.

"There's always an establishment, and these guys are plugged into it," observed Bob Scheer, a veteran columnist for the Los Angeles Times. "There are adults watching the store."

But disengagement carries with it its own dangers. Bush has already been accused of losing interest in the Middle East (a perception that prompted another overseas call from his dad). Too often he sounds like the pampered son of privilege, as when he commended Cheney's latest highly expensive heart procedure to other Americans without realising that most of them cannot afford it.

Worst of all, he is a President who doesn't like to read briefing papers, or deal too closely with policy himself, and yet he is happy to make rapid decisions on any number of crucial issues. As Frank Rich wrote recently in the New York Times: "He is a man who does not know how much he does not know, and seems in no rush to find out." If he is treading down policy paths that infuriate and antagonise the rest of the world, he is probably the last person to find out, or even care.

Andrew Gumbel is the 'Independent on Sunday' Los Angeles correspondent