The essays in this collection were written well before Osama bin Laden was killed by the US Navy SEALs in early May. His death marked the end of the September 11 decade, even though the 10th anniversary was still over four months away. Though the themes explored in this volume remain important, the question of what changes with bin Laden's death is worth asking.

Of course, no one yet knows exactly what bin Laden did from his Pakistani hideaway. On some readings al-Qaeda had been emasculated and sidelined from the action for years. On other interpretations it had morphed into an even more dangerous hydra-headed threat to international peace and security. But whatever bin Laden's tangible influence on global affairs in recent years, his psychological impact has remained profound.

Now he is gone. The smart money says this will only underscore three big trends that were under way long before his death: the Obama doctrine of getting out of existing, and avoiding new, foreign entanglements; Obama's clear pitch for re-election in 2012 as the president who undid Bush's wars and refocused America on the big challenges at home; and re-orienting the battle with radical Islam away from counterterrorism and towards more conventional international relations, above all in Iran and Pakistan.

The Obama doctrine that has emerged slowly but surely in the past two-and-a-half years will likely be even clearer in the post-Osama era. Put simply, that doctrine is to undo as quickly as possible George W. Bush's misadventures not only in Iraq, the wrong war from the beginning for Obama, but also in Afghanistan, which he embraced as the right war in the 2008 presidential campaign. Obama's reticence to take the fight to Gaddafi in Libya, despite the Libyan regime's potential to derail the freedom march of the Arab spring, also shows that the national-interest bar for US military intervention is now high.

Bush showed no compunction in playing the al-Qaeda card to justify staying the course in Iraq and Afghanistan. Now Obama can play his bin Laden card for the polar opposite purpose, to explain why the US is taking a big step back from Bush's wars. He will never use any of Bush's triumphalist rhetoric. But the message will be clear in actions if not words. Most importantly, Obama's timetable for beginning the draw down in Afghanistan in the middle of this year and getting out completely in 2014 looks even more locked in, and his resolve not to commit boots on the ground to other Middle East hot stops is likely to be redoubled.

The second consequence of killing bin Laden is that it makes more likely the re-election of Obama. For years America's radical right has engaged in a successful whispering campaign linking Obama to the Muslim world. The innuendo may have had no foundation, but it has had political impact. Now Obama can respond to any and all such charges with a matter of fact "I did what Bush couldn't; I got Osama". This response will also be very effective in disarming more sober but not less intense criticism of Obama from the Republican establishment that he is weak on national security.

Obama's immediate post-Osama spike in the opinion polls is likely to be short lived. But the right will think twice before attacking him on foreign policy knowing that Obama can neutralise them in an instant. At the same time, Obama's drawdown in Afghanistan and staying on the sidelines in Libya will continue to play well electorally in a country sick and tired after a decade of war.

Entrenching the Obama doctrine and refocusing American politics on domestic issues does not mean the US will face no foreign policy challenges in the post-Osama world. Far from it. Looking at some of these challenges will be the subject of the second part of our 10th anniversary of September 11 special, in August.

For 10 years the US has groped around for the right strategies to take on shadowy figures, amorphous opponents and unconventional weapons of the weak. Now the sharp edge of US foreign policy can be pointed at more conventional and readily identifiable foes, big powerful nation-states led by repression-based governments with worrying objectives. The US and the West's challenge with Iran and Pakistan may be diabolical, but it is a long way from the war on terrorism as it was understood during the September 11 decade. Bin Laden's death will give Obama the clear air he needs to focus on it, with the epitaphs probably not due until lat 2016.