On May 20-22, Nato will hold a summit in Chicago to discuss the alliance's global military reach.

Among other issues it will consider the war in Afghanistan and its nuclear doctrine.

Why is this important? For a start, Britain remains embroiled in that war. Over 400 British troops have already died in the conflict, alongside countless Afghans, including many civilians. But according to our government keeping up the occupation is "vital for our security."

Second, Nato - unbelievably - still maintains a "strike first" policy with regard to nuclear weapons. It's committed to "nuclear sharing," too.

This isn't a very accurate term, since the US does not share its thousands of nuclear warheads - it simply means it gets to station them in other people's countries, with nuclear-armed Nato bases strewn across Europe and beyond, from Belgium to Incirlik in Turkey.

At Nato's Lisbon summit in 2010 Nato reaffirmed its nuclear policy "while other states have nuclear weapons," without acknowledging the Nuclear Non-Proliferation Treaty whose signatories are supposed to pursue disarmament "in good faith."

Nato continues to trot out the message that member-states need a nuclear deterrent. This deterrence theory was and is a lie. Nato itself admits that one of the prime threats to citizens in its member-states is from terrorist attacks - but how are nuclear weapons supposed to counter that threat? The September 11 2001 attacks on New York took place despite the fact that the US had 14 Trident submarines operational at the time.

Beyond that this summit is important because President Obama is looking for some cuts in his military budget - as well he might, since it accounts for over half the military spending in the world. So in a speech to the Pentagon in January Obama said European countries would have to contribute more - or rather "take more responsibility for collective security."

What was the British response? Parliamentary Undersecretary of State for Defence Gerald Howarth MP gushed that Nato was "the cornerstone of our collective security."

It was the organisation that "many other countries look to," he said, not noting that most of them do so with fear and alarm or what Russia and China make of being encircled by a predatory alliance armed to the teeth.

Nato was a community of allies with values, "ready to back principles with power."

It begs the question as to what those principles are. Bombing civilians in Afghanistan? Threatening the world with annihilation?

Some Nato states weren't pulling their weight, the minister lamented - arguing that "those of us who understand the volatility of the modern world and the dramatic shifting of tectonic plates" (whatever that's supposed to mean) "need to make the case for defence spending."

Talking of "re-prioritising" spending - at a time of drastic cuts - he added that "all the investment in our schools and hospitals - or indeed welfare - could be set at naught if we fail to provide adequate defence."

The minister then talked of abandoning "the consensus voting of 28 Nato members" and of the "few" using Nato assets "on behalf of the many." This, presumably, means making it easier for the most aggressive states in the alliance to coerce the rest into bankrolling their wars.

"The United States will be watching closely," he said. "So too will our adversaries. The Chicago summit provides the perfect opportunity to show them all that when it comes to defence and security Europe remains committed, capable and solvent."

Brushing aside the tacit acknowledgement that Europe doesn't currently look capable or solvent in any other regard, the important point is that defence and security are just euphemisms for military power when used by Nato states.

The alliance was, supposedly, founded to counter the Soviet threat, though its establishment predated that of the Warsaw Pact. But the end of the cold war didn't mean the end of Nato.

Through the 1990s Nato built up its membership across central and eastern Europe right up to the Russian border.

It has engaged in "partnerships" with Mediterranean countries and carries out military exercises with Israel, exacerbating the ferment in the Middle East. It has also been hard at work collaborating with other US-led alliances in other parts of the world - Trident submarines "integrated" into Nato regularly cruise the South China Sea.

And since the end of the cold war the alliance has become much more aggressive. Foreign policies are increasingly influenced by the the thirst for profit of huge weapons-manufacturing firms. The US owns many of these but Britain and France aren't that far behind.

That's why when ex-Soviet bloc states joined they had to scrap their Soviet hardware and buy in US planes for "interoperability."

It's no coincidence that Bruce Jackson, who was chair of the Nato expansion committee and now heads the ominously named Project on Transitional Democracies which hopes to integrate countries into the "Euro-Atlantic," was Lockheed Martin's vice-president for strategy and planning from 1993-2002.

Whose planes did the eastern European countries have to buy when they joined Nato? Lockheed Martin's F-16s. Many are still bearing the brunt of the huge expenditure as Lockheed Martin laughs all the way to the bank - even the beleaguered Greek people are still paying millions of euros for their shiny new fighter-jets.

Nato's close connection with the military-industrial complex, its maintenance of vast nuclear weapons systems, its constant talking up of supposed enemies are all putting British lives in danger without mentioning the residents of its "adversaries." The alliance is creating further world instability.

Security this is not, and the huge sums spent on weaponry are obscene in an age of "austerity."

But there is resistance. A No to Nato Network has been established and is calling for international days of action. On Saturday 19 May Stop the War and CND have called a Say No to NATO protest at the US Embassy in London. It's time we stood up to the militarism of our rulers.

Don't Attack Iran, Troops Out of Afghanistan
No Intervention in the Middle East
Protest and Rally Saturday 19 May 1pm
US Embassy Grosvenor Square London W1

Called by Stop the War Coalition and CND