Europe owes a huge thank you to skilful, patient President George Bush

Future historians will record that Europe owes much to George Bush. With patient, accomplished statecraft, they will note, he played midwife to a historic unification of eastern and western Europe. His handling of Russia was little short of masterly. At the same time, he built an impressive international coalition to defeat Saddam Hussein.

I refer, of course, to Bush the father - George HW Bush. Pity about the son. As George Bush Jr makes what is probably his last official visit to Europe, attending a rancorous Nato summit in Nicolae Ceausescu's megalomaniac "palace of the people" in Bucharest, it is painful to reflect how much the father did for Europe in four years and how little (to put it mildly) the son will have achieved in eight.

Many of the cardinal points of his European policy pop up in Bucharest, either formally or informally. Take missile defence, for starters. Bush came on his first official visit to the old continent in summer 2001, determined to convince us Europeans of the importance of missile defence; and he still seems convinced of it himself. So this futuristic project - the son or by now grandson of Ronald Reagan's Star Wars - keeps grinding forward, with the assistance of increasingly reluctant Poles and Czechs. The trouble is that it's largely irrelevant to the principal security threats of the post-9/11 world. Bush profoundly observes that "a missile can fly north just as it can west" - thus pointing the finger at Iran as well as Russia. But the idea that you best defend yourself against a potentially nuclear-armed rogue state by doing a modernised version of what Ronald Reagan 20 years ago imagined you might do against the old nuclear-armed Soviet Union is about as intelligent as holding a large umbrella over your head while the floodwaters lap around your thighs and piranhas gnaw at your heels. Different times require different answers.

Then there's Afghanistan, where western democracies are in danger of losing a war we once thought we had won. Unlike some on the European left, I regard the war against al-Qaida and the Taliban in Afghanistan as entirely justified. But in one of the most unforgiving places on earth, this battle was always going to be tough, calling for focus, endurance and a multilateral coalition sustained by skilful leadership. That is what Bush Jr has failed to deliver.

Recall that after the 9/11 attacks, Nato invoked its famous Article 5 - one for all and all for one! - for the first time in its history, and offered its services in Afghanistan. The then secretary of defence, Donald Rumsfeld, spurned this offer of solidarity from European and Canadian allies. Washington's court chronicler Bob Woodward summarises Rumsfeld's response at a top-level White House meeting: "the coalition had to fit the conflict, not the other way round ... Maybe they didn't need a French frigate." Seven years on, Washington is begging for a thousand French soldiers to help shore up the Canadians' valiant struggle against the resurgent Taliban.

The main reason we are in this desperate state is that, before the blood was dry in the mountains of Afghanistan, the Bush administration charged off on an unjustified, ill-judged and eventually disastrous adventure in the deserts of Iraq. Five years on, even those who still maintain that the Iraq war was justified will agree that its execution was monstrously incompetent. Both a retired American military commander and a very senior former National Security Council official have explained to me in detail how this King George (II) simply failed to choose between alternative policies advanced by his over-mighty barons in the Pentagon, the State Department, and the vice president's office (Baron Dick). At any given time, the United States had two or three strategies in Iraq - and therefore none.

In short, the W in George W stands for weak. For all the macho Texan swagger - "your man [Blair] has cojones" and so on - this Bush has been, on the things that really matter to the world, a weak president. Whereas the outwardly mild and preppy George Bush Sr was, on things that really mattered to the world, a strong president - that is, an effective practitioner of international statecraft. Bush the son reportedly has a complicated relationship with his father, some would even say a complex. Well Oedipus, shmoedipus ... but daddy did better.

Not that he got everything right. Bush Sr's patient, consensus-building realpolitik had the vices of its virtues. By failing to follow through to Baghdad, in order to keep the coalition intact, he did store up trouble for his successors, as he did by an all too "realist" alliance with the House of Saud, while their Wahhabi clerisy preached petrodollar-funded hate in mosques right under our noses. And his own visit to Ukraine in 1991, with its infamous "chicken Kiev" speech, effectively calling on Ukrainians not to pursue independence - something they had a perfect right to do, and were probably going to do anyway - was a low point.

Unlike many in Europe, and in Washington these days, I essentially agree with Bush Jr in his implicit criticism (shall we call it OedipoKantian?) of the shortsightedness of Bush Sr's soi-disant realism in places like Saudi Arabia and Ukraine; in his claim, as a somewhat unlikely follower in the footsteps of the philosopher Immanuel Kant, that ultimately the spread of liberal democracy is the best guarantee of peace; and in his insistence that neither Vladimir Putin nor his successor have any right to dictate to Russia's neighbours which alliances they should join. It's the execution that has been so disastrous; the statecraft that is wholly lacking.

Compare Germany 1990 and Ukraine 2008. You can read in an excellent historical account by two junior members of the Bush Sr administration, Philip Zelikow and Condoleezza Rice (the same), how skilfully he brought reluctant allies like Britain and France to accept German unification, and how brilliantly he soft-talked Mikhail Gorbachev into accepting that united Germany could be in Nato.

Today, Bush Jr faces a public revolt by united Germany and France over his proposal to put Ukraine on an explicit track to Nato membership, with a so-called membership action plan. Vladimir Putin is, admittedly, a tougher nut to crack than Gorbachev, and Russia is still on the rebound from Gorbachev's generous concessions, but the timing of Bush's forward thrust is also maladroit - just before Putin hands over to his successor. And a majority of today's Ukrainians don't even want their country to be in Nato. Had Bush Jr taken a leaf out of his father's book, or at least read Condi's; had he done the intensive, private diplomacy with allies and with Moscow as well as the public diplomacy in Ukraine; called in yesterday's favours; chosen his moment; worried less about form than about content; then the US could, over a number of years, have achieved the desired result in partnership with its European allies. Instead, he's making yet another unilateral cod's ear.

But let's not be too negative. After all, this summit will usher Croatia and Albania into the fold. That may not quite match daddy's achievement with Germany, but it's something for the history books, isn't it? Say what you like about George Jr - he'll always have Albania.

Timothy Garton Ash