[en] The very existence of nuclear weapons gives rise to the pursuit of them. They are seen as a source of global influence, and are valued for their perceived deterrent effect. And as long as some countries possess them (or are protected by them in alliances) and others do not, this asymmetry breeds chronic global insecurity. The present nuclear-arms-control regime is looking battered. But any reform of that regime must begin by conceiving a framework of collective security that does not rely on nuclear deterrence. The rise of terrorist groups makes this essential. A nuclear deterrent is clearly ineffective against such groups; they have no cities that can be bombed in reply, nor are they focused on self-preservation. Moreover, their constantly shifting targets and modes of attack demand a more co-operative and flexible international response. The 'war on terror' should provide an impetus to work towards a global security culture that will serve the interests of all countries equally, and will make reliance on nuclear weapons obsolete