If George Bush were proposing what Obama proposed at the Nato summit last weekend, many would now be railing against him. But he’s not George Bush. He’s modern jazz to Bush’s barn-dance.

Svelte and eloquent, with a wife the epitome of cool and the most charming of children, Obama comes on as both a contented family man and a celebrity intellectual. Plus, he has a reservoir of goodwill to draw on. He can do things that Bush wouldn’t dare, while maintaining trust and credibility at home and abroad. So far.

At Strasbourg, Obama made plain he intends to proceed with his plan to increase US troop levels in Afghanistan from 38,000 to more than 60,000. But, as the New York Times reported from Strasbourg, “His calls for a more lasting European troop increase were politely brushed aside.” Five thousand fresh European soldiers will be concentrated in areas outside the main combat zones and are committed only until Afghan elections in the autumn.

“I want everybody to understand that our focus is to defeat Al Qaeda,” Obama told the Nato gathering. What is this but a restatement seven and a half years later of Bush’s rationale for invading Afghanistan in the first place? Back in 2001, for Americans in particular, it made a sort of emotional sense. Bin Laden’s outfit had its operational headquarters and main training facilities in Afghanistan.

But not any longer. All reports and intelligence estimates agree that Al Qaeda has long ago relocated, mainly to border regions of Pakistan.

The military or political point of pouring more resources into the Afghan occupation at this point is far from clear. What it suggests is that the occupation is becoming bogged down.

In Pakistan, too, precedent tells that the Obama strategy of extending the US military effort may be headed for disaster. Unlike its neighbour, Pakistan is not relatively small (180 million as against 20 million people), chronically underdeveloped, with few natural resources and minor strategic significance. It is a nuclear power of importance to US global strategy and with separate and distinct interests of its own.

Yet, far from being calculated to win the hearts and minds of the Pakistani people and help maintain the country’s stability, US intervention might have been designed to create enemies and alienate people. Pakistani government officials were quoted at the weekend saying that, “American drone attacks on the border are causing a massive humanitarian emergency ... As many as a million people have fled their homes in the Tribal Areas to escape attacks.”

Tom Hayden made the relevant point in the Huffington Post on Monday: “Military occupation, particularly a surge of US troops into the Pashtun region in southern Afghanistan and Pakistan, is the surest way to inflame nationalist resistance... The levels of suffering are among the most extreme in the world, and from suffering, from having nothing to live for, comes the will to die for a cause.”

Other aspects, too, of US policy in the region haven’t changed for the better under Obama. His executive order against torture appears not to apply to Afghanistan. The notorious Bagram prison outside Kabul, its walls the colour of dried blood, is not being closed down but is undergoing major expansion.

Obama was born the year Kennedy became president. The neat coincidence might have persuaded a man as erudite as himself to read up on Vietnam. But apparently not. (Contrary to myth, it was Kennedy, not Johnston or Nixon, who took America into Vietnam.)

Vietnam rather than Iraq may provide the precedent and parallel. The initial declaration of an idealistic motive, the subsequent confidence that conditions can be created for early, honourable withdrawal, the projection of an enemy threatening the region, even the world, bafflement as the mission becomes mired in a cloying reality, semi-covert widening of the battlefield across national borders, surges of troops and escalation of weaponry to regain momentum towards victory, growing hostility among the local population, gathering anger and disillusionment at home...

The Carnegie Endowment spelled it out for him in January: “The only meaningful way to halt the insurgency’s momentum is to start withdrawing troops” — which is what many Americans, naively perhaps, trusted would happen when they swarmed to give Obama their votes.

Obama was always going to face a contradiction between the huge expectations his campaign engendered and the practicalities of office.

He bracketed himself with Lincoln and Roosevelt, quoted Frederick Douglass (“Power concedes nothing ... we are going to have to struggle”) with approval, repeatedly made reference to the civil rights movement, suggesting a radical challenge to the existing order while inviting measurement against a high standard. Last weekend, as he struggled unsuccessfully to bring his partners with him on the Afghan adventure, Washington’s Pew Research Centre — an independent non-profit ‘fact tank’ — reported that, contrary to widespread perception, American politics is more polarised now than at the equivalent points in the presidencies of Nixon, Reagan, George Bush or George W.

This has less to do with Democrats deserting Obama than with Republicans stiffening against him. It represents a return to sharp partisanship.

Obama still has a lot going for him. But maintain political dominance and popularity back home and the goodwill of the wider world while continuing the occupation and raising the stakes in Afghanistan and Pakistan?

No, he can’t. Sooner than expected, for Obama a crunch is coming.