GMF - The German Marshall Fund of the United States - Strengthening Transatlantic Cooperation

When western security experts gather this weekend in Munich to discuss the future of Nato at their annual security conference, they will be considering an Atlantic alliance that faces two rather stark choices: re-reinvent itself to handle the threats of a new century, or watch itself drift slowly into strategic marginalisation.

I say "re-reinvent" because Nato once before reinvented itself, in the 1990s. Back then, the question was what to do in the wake of the cold war. After fierce debate, Nato members opted to enlarge the alliance to encompass central and eastern Europe, intervene in the Balkans and establish a new if bumpy relationship with Russia. With the benefit of hindsight, this strategic leap looks almost self-evident. At the time, however it was anything but that, and involved more than one near-death political moment as members brawled over the issues before them.

We now look back at the 1990s as the lull before the storm - the inter-war period between the cold war and the onset of a new war against radical Islam and terrorism. But as these new threats have appeared, Nato has failed to keep pace. The alliance must be re-reinvented because the US and Europe face a set of real and growing threats in an "arc of crisis" stretching from northern Africa through the wider Middle East to Afghanistan and into central Asia. Instability across this region arguably poses the greatest threat to global stability since the early 1960s and the Cuban missile crisis.

Nato alone cannot solve these problems. There must be a broader strategy that integrates civilian and military means. Yet, that strategy must also include the ability to act militarily to help bring stability to these troubled regions. Plain and simple, Nato must become a more global alliance that takes it to places beyond the European heartland and on missions beyond the imaginations of the founding fathers if it hopes to remain a relevant alliance that addresses the main challenges of our era. Nato's biggest test is taking place right now in Afghanistan. It is the first, but certainly not the last, time Nato members will fight an unconventional war beyond Europe with global partners that require a co-ordinated civilian and military effort with the European Union and United Nations. But the war there is not going well. Afghanistan will be with us far longer than Iraq and a defeat there would be catastrophic.

The sheer difficulty of generating political will within the alliance to produce the necessary resources underscores the fact that Nato allies have not yet grasped the new threats faced or the stakes involved.

When it comes to the other hotspots in this arc of crisis, Nato is largely missing in action. Yet there are clearly issues where a reinvented Nato could help make a difference. One is Iraq. While we should do everything possible to maintain Iraq's unity, it is clear the country could fragment. This will directly affect Nato members, above all Turkey. The best way to reduce that risk would be for Nato to be prepared to deploy troops to northern Iraq to help contain the spillover of an Iraqi civil war.

Nato took a pass when it came to deploying troops in southern Lebanon. Yet one can envisage scenarios where more muscular reinforcements are needed and if such a situation emerges, Nato should be ready. The alliance should also expand its political dialogue in the Middle East. Even as the west seeks to curb Iran's nuclear aspirations, Nato should deepen its relations with the Persian Gulf states and Israel. If the shock of Balkan ¬ethnic cleansing lent impetus to the reinvention of Nato a decade ago, today's horror in Darfur should do the same.

A centrepiece of the alliance's reinvention in the 1990s was enlargement. Nato's door must remain open for countries in the Balkans as well as candidates such as Georgia and Ukraine across the wider Black Sea region. This is especially true if, as seems likely, the EU's doors are closing. Such a policy could help stabilise the southern flank of the Euroatlantic community and counter spillover effects from an unstable Middle East.

It is time to stop pretending that all is fine in Brussels. An open debate is needed about fixing the alliance and making the strategic leap to a new era. Nato must be re-reinvented to confront the gathering dangers we face. How to do this is the question that should be central to the discussions in Munich this weekend. At stake is nothing less than the west's ability to meet fully the strategic challenges of our time.

The writer is executive director of the German Marshall Fund's Transatlantic Center in Brussels