Over the past few months, Britain's armed services have been in crisis. Again.

You know the drill. The weapons the forces want to buy will bust the defence budget, so cuts have to be made. The services leak furiously against each other, each valiantly trying to shove the others towards the chopping block.

In December, Defence Secretary John Hutton adopted the time-honoured remedy: cancel nothing, but delay a lot - those new aircraft carriers will have been talked about for two decades before they arrive, if they ever do. With delays, of course, come higher costs.

And all the while, the forces shrink and the Ministry of Defence proclaims there is no cause for alarm. That's particularly laughable now that the MoD's been put on the hook by the Treasury for most of operational costs in Iraq, and also Afghanistan where Britain suffered its 150th fatality this week since hostilities began in 2001.

That will turn the Treasury's proclaimed £500m increase on defence into a £1.2bn cut. Sure, the Treasury always wins, but for Hutton to do that badly, the forces must have been in an even deeper hole than he let on.

The Treasury's claw-back is standard stuff. They know how to work a crisis. But when crises keep on happening, they're not crises. They're normal, and that's not the same as good. Britain's forces are in a hole. Here's why.

There are three things you have to get right if you want to have a sensible defence policy. How much you spend, what you buy with it, and doctrine, or what you plan to do with what you've bought.

The cure for Britain's forces is not simply more money. It's true that Labour's taken Britain perilously close to the precipice. Defence spending now is 2.3 per cent of GDP. The last time Britain went lower was in 1933. By 1939, that didn't look so smart.

So spending needs to rise. Historically, 4 per cent of GDP is a reasonable level. Set that as the target, so the forces aren't nibbled away by demands for peace dividends, and move towards it gradually, over the next decade.

But just spending more money is no cure. Procurement's broken too. The Government uses it as a wildly inefficient welfare policy. It buys at home, even if what it buys is expensive, because it's a way of paying off the trade unions.

Buying British is not an assertion of sovereignty. That's not a knock on Britain. But it's a fact that most everything the British forces use has American or European components in it already.

The US should buy British if it is efficient. And Britain should buy American when it needs to. Defence should be about defence, not about showering workers in key constituencies with wasteful contracts.

But it's hard to know what you want to buy unless you know what you're going to use it for. Even the US can't cover every contingency. Britain certainly can't afford to do so.

But Britain doesn't really think about doctrine. When the Strategic Defence Review came out in 1998, the big concept in it was "jointness". All the services would co-operate with each other, which, conveniently, would both save money and make them better.

Of course, "jointness" didn't work out as planned. But the real problem is that "jointness" was a US concept: Britain ripped it off from the US's Joint Vision 2010, which came out in 1996. Then, in 2003, Labour shifted to emphasising "transformation". That was a US idea too, associated with then-Secretary of Defence Donald Rumsfeld.

There are a couple of problems with Britain's relentless copying of the U.S. First, sometimes the US gets it wrong. And second, even when the US is right, America's defence budget is 10 times as big as Britain's.

The kind of doctrine you have, the kind of weapons you buy, and the amount of money you spend are all connected. Or at least they should be connected. Copying US doctrine without copying the US's budget means you won't have enough money to go round. And that's why the British forces are always falling short.

So fixing the problem doesn't start with money. It starts with recognising why Britain has armed forces. Like any democratic state, Britain maintains its forces for two reasons: to deter potential adversaries, and to beat them if they play rough.

This Government has decided that future wars are going to be light, Afghan-style affairs. Therefore, it doesn't need to buy anything heavy, like tanks. Conveniently, heavy things are also expensive. The Government's crystal ball is really all about saving money.

Even on its own terms, this vision is foolish. No one knows what the future of war holds. People who are sure they do invariably end up looking very silly, very dead, or both.

And light forces, no matter what their other merits, are not good at deterrence. Trident is not the answer: Britain should keep it, but relying on nuclear weapons alone is not something a liberal state should get comfortable with.

That means Britain, to deter and to win, needs balanced conventional forces, ones that don't rely on the magic-wand victories of "transformation". And that means Britain needs to raise its defence budget and emphasise efficiency in procurement.

The fact that Britain does not connect money, procurement, and doctrine coherently is not the fault of the forces. The real problem is that neither the politicians nor the British people take defence issues as seriously as they used to.

In the most recent list of Cabinet precedence, the Ministry of Defence was in 10th place, behind the Department of the Environment, Food and Rural Affairs. That is a European order of priorities. The British people are proud of their armed forces, but, like the continent, they do not appear to want to make a sustained national commitment to defence.

That will not work. If the defence crises are to end, a firm commitment of care, money, and above all of sustained thought will have to be made. And it needs to be made. An under-armed Britain is not simply failing in its duties to its citizens, to Nato, and to its men and women in uniform. It is tempting predatory powers to take chances.

The world's democracies tried that strategy in the inter-war years. It failed miserably. There is no reason to try it again.

Ted Bromund is a senior research fellow in The Margaret Thatcher Centre for Freedom at the Washington-based Heritage Foundation.