How much more true it is in our open world today: a world where deadly weapons can be obtained not only by rogue states but by extremist groups; a world where SARS, or avian flu, can be carried across oceans, let alone national borders, in a matter of hours; a world where failed states in the heart of Asia or Africa can become havens for terrorists; a world where even the climate is changing in ways that will affect the lives of everyone on the planet.
Against such threats as these, no nation can make itself secure by seeking supremacy over all others. We all share responsibility for each other's security, and only by working to make each other secure can we hope to achieve lasting security for ourselves.
And I would add that this responsibility is not simply a matter of states being ready to come to each other's aid when attacked – important though that is. It also includes our shared responsibility to protect populations from genocide, war crimes, ethnic cleansing and crimes against humanity – a responsibility solemnly accepted by all nations at last year's UN world summit. That means that respect for national sovereignty can no longer be used as a shield by governments intent on massacring their own people, or as an excuse for the rest of us to do nothing when heinous crimes are committed. Whole speech here