Last week the Pentagon asked Congress for the biggest defence budget since the Second World War: $515 billion, plus an additional $70 billion to cover the costs of the wars in Afghanistan and Iraq for part of the coming year. The United States is proposing to spend more on the armed forces, quite apart from the running costs of Iraq and Afghanistan, than it did at the height of the Cold War against the Soviet Union – and yet almost all the commentary and analysis in the US media has focussed on the spending on the two wars.

Even that is a lot of money. The US Congress has already approved $691 billion in spending on Iraq and Afghanistan since 2001, and the total estimate for this year alone is $190 billion. Not only that, but some of the money in the regular defence budget can also be indirectly attributed to America’s wars in the Muslim world, like the expenditure on new equipment to replace the weapons that have been destroyed or worn out in the wars.

But there is a great deal more money in the current US defence budget – probably three times as much – that has nothing to do with the "war on terror." Even if you accept the deeply suspect proposition that invading foreign countries is a useful way to fight terrorism, invading the target countries (which generally do not inhabit the higher reaches of the technological pecking order) does not require eleven aircraft carriers and fleets of stealth bombers.

So what is all the rest of the money for? According to Michael Klare, defence correspondent for "The Nation", the answer is obvious.

"The US military posits its future on the China threat. That is the ultimate justification for a defence budget of $500 billion a year. There is no other plausible threat. If you look at the new budget which came out just this week, it calls for vast spending on new weapons systems that can only reasonably be justified by what they call a "peer competitor", a future superpower that could threaten the United States, and only China conceivably can fill that bill. Not Iran, not Iraq, or some (other) rogue state. Only China fits that bill."

It’s obvious, when you think about it. If the United States had no present or prospective "peer competitor", how could the Pentagon justify spending huge amounts of money on next-generation weapons? For beating up on "rogue states", last-generation-but-one weapons are more than adequate. So there has to be a peer competitor, whether it understands its role in the scheme of things or not. And only China can fill that role.

So what is the alleged competition about? Energy, of course, and mostly oil. Michael Klare again: "The Pentagon and US strategists talk openly about US-China competition for energy in Africa, in the Caspian Sea basin, and in the Persian Gulf, and they talk about the danger of a China-Russia strategic alliance that the US has to be able to counter. This is very much part of US concerns. They talk about the Shanghai Cooperation Organisation as a proto-military alliance that threatens America’s vital interests.

"Terrorist assaults and skirmishes with Iran or some other rogue state are more likely on the curve of probability, and the military is geared to fight these kind of regional skirmishes....But when they talk about the greatest threats that they might have to face, for which they have to allocate their largest sums and acquire their most potent weapons, it’s the China-Russia alliance that they’re preparing for and asking Congress to allocate the largest sums of money for."

What the US military are not doing, for the moment, is telling the American public that China is why they want all that money. The amorphous, infinitely expandable "war on terror" can be used to cover all sorts of other expenditures as well. Nobody is required to prove that China really does pose a strategic threat to America’s oil supplies, or to demonstrate that a Chinese-Russian alliance is a serious political possibility.

But that happy time is probably coming to an end. As the "terrorist threat" gradually shrinks down towards its true, rather modest dimensions in the minds of American voters and even American politicians, the wisdom of spending so much money on a strategic confrontation with China that does not yet exist – and may never actually come to pass – is bound to come under question.

As for an enduring Chinese-Russian alliance, the notion is about as credible this time round as it was back in the early days of the Cold War. Since China is the country that poses the greatest potential threat to Russia, it can be a good short-term strategy for Moscow to hug China close. But the alliance lasted only thirteen years last time (in the early years of the Cold War), and it would probably not survive even that long on a second occasion.