Texas A&M is not the obvious place to pick if you want to discuss American decline. The university sends more of its graduates straight into the military than any other civilian college in the US. Its officer training corps prowl the campus in crisply pressed uniforms and knee-high leather boots, greeting each other with brisk “howdys”. Agonised introspection and crises of confidence are not Texan traits.

But last week the Scowcroft Institute of International Affairs at Texas A&M hosted a conference designed to discuss the latest, markedly gloomy world view issued by America's intelligence establishment. Every four years the National Intelligence Council – which oversees America's baroque collection of intelligence agencies – releases a global trends report, which is given to the new president.

The latest report, published on November 20, has made headlines around the world. The front page of Britain's Guardian newspaper shouted “2025: the end of US dominance”. For once, the headline is broadly accurate. As the NIC frankly notes, “the most dramatic difference” between the new report and the one issued four years ago is that it now foresees “a world in which the US plays a prominent role in global events, but the US is seen as one among many global actors”. The report issued four years ago had projected “continuing US dominance”.

The NIC report has made people sit up because it comes from the heart of the US security establishment. But it is part of a broader intellectual trend in America: a “new declinism”. This mood marks a complete break with the aggressive confidence of the Bush years and the “unipolar moment”. Its starting assumption is that America, while still the most powerful country in the world, is in relative decline.

Three developments have fed the new declinism. First, the wars in Iraq and Afghanistan have underlined that US military supremacy does not automatically translate into political victory. Second, the rise of China and India suggest that America's days as the world's largest economy are numbered. Third, the financial crisis has fed the notion that the US is living beyond its means and that something is badly wrong with the American model.

This gloomy mood was captured by the opening address to the NIC's conference, given by none other than General Brent Scowcroft himself, returning to the institute named after him. The general noted that the US had found itself in a position of huge global power after the end of the cold war, which was “heady stuff”. But “we exercised that power for a while only to realise that it was ephemeral”.

This new awareness of the constraints on American power is reflected in a number of new books and articles. The most influential is probably Fareed Zakaria's The Post-American World, which is said to be the only book on foreign affairs read by Barack Obama this year. Although Mr Zakaria strives to present the rise of China, India and “the rest” as unthreatening to the US, the inescapable conclusion is that the Bush years marked the apogee of American power.