If you’ve only got limited time, I’d rather you went and read the text of Barack Obama’s address last week at the National Defense University. I think it’s much more interesting and intelligent in its own right than anything that I’ve got to say about it.

In particular, don’t miss his exchange with an interjector who demands the closure of Guantánamo Bay, which concludes with Obama saying “The voice of that woman is worth paying attention to.” Not many leaders deal with hostile interruptions in such a respectful fashion.

It’s not quite the rhetorical Obama that were used to; it’s a bit more discursive, showing us a bit more of his thinking process. One analyst said he “sounded like a former constitutional law lecturer who sees the nation and its security challenges in more shades of gray than he once did.”

The basic idea is that “war on terror” must not be allowed to become an open-ended commitment, that the period during which it could properly be described as “war” at all is coming to an end, and what remains are limited campaigns against specific targets, not a global conflict with an all-embracing enemy. The president says his objective is to “continue to fight terrorism without keeping America on a perpetual wartime footing.”

Obama is still treading cautiously on particular measures, and some will say he should go further and faster. I for one am far from convinced by his defence of drone warfare. But it’s the general outlook that’s significant; as John Cassidy put it in a very sensible review of the speech in the New Yorker:

It didn’t just question the utility of individual measures, such as holding prisoners without trial, it queried the intellectual underpinnings of the whole war-on-terror enterprise, the entire mindset that has gripped the country for the past eleven and a half years.

Of course Obama is not the first to do that; some of us have been saying from the start that this whole approach was wrongheaded. One might mention, for example, Hugh White back in 2006 pointing to the “message that terrorism poses an existential threat” and remarking that “to the calmer view of future historians this conviction, which is apparently self-evident to so many people today, will seem surprising, even bewildering.”

But a lot of people have invested a lot of emotional capital in the idea of “war on terror”. Republican senator Saxby Chambliss said the president’s speech “will be viewed by terrorists as a victory” – the very extravagance of the language suggests that there is something more than political point-scoring at work, and that downgrading the war threatens something deep in the Republicans’ worldview. (An article in Haaretz suggested that the Israeli government will have similar reservations.)

The reality is that militarising the conflict against terrorism, both in rhetoric and in practice, has mostly worked against the interests of the United States. Guantánamo and associated abuses have provided fresh recruits for Al-Qa’eda; the invasion of Iraq gratuitously opened a whole new front; drone warfare in Pakistan has been a public relations disaster.

Towards the start of his speech, Obama said that “Most, though not all, of the terrorism we faced is fueled by a common ideology – a belief by some extremists that Islam is in conflict with the United States and the West, and that violence against Western targets, including civilians, is justified in pursuit of a larger cause.” But this is a half-truth, and it can be a dangerous one. Islamic fundamentalism may provide a convenient rationalisation, but most actual terrorists seem to have been driven by much more specific grievances.

Putting America on a war footing is one of the things that has done the most to bring forth warriors against it. The metaphor has become self-fulfilling. If Obama can succeed in dismantling and discrediting it, he will have done a lot to earn his Nobel peace prize.