Director, Centre for International Relations, Queen's University. An earlier draft of this article was presented to the conference on national missile defence sponsored by the Canadian National Committee of the International Institute for Strategic Studies, Toronto, 10-11 May 2001. I am grateful for research support provided through the Security and Defence Forum (SDF) of the Department of National Defence, Ottawa.INTRODUCTIONDifficult as it may be in the wake of the historic developments of and subsequent to 11 September 2001, it is useful to recall that, not so very long ago, we were all making a fuss about the 'turning' of the millennium. Part of the fuss concerned the timing of this transition, with purists insisting it took place on 1 January 2001 and not the year before, as the vast majority thought. But nearly all agreed that, whenever the last century expired and the new one began, the passage of time was well worth marking. For those of a geostrategic bent, it was doubly worth marking because it appeared as if one arms initiative in particular, the American proposal to build a national missile defence (NMD) system, loomed as the issue of the new age, something that proponents and critics alike understood had the potential to be the seminal marker in the twenty-first century's balance of power.For the critics, NMD's defining trait resided in the harm it was thought capable of inflicting upon global arms control, especially given the critics' worries about an arms control regime that was seen to be tottering ever more on the brink of obsolescence and whose fall must usher in a new and sinister phase of 'arms-racing.' Nor did it help the critics' mood when they contemplated NMD's symbolic portent - the onset of a new age of isolationism in American foreign policy, with all that this must entail for the interests of the country's allies, Canada among them. The supporters, for their part, were equally convinced that the world was becoming ever more menacing because of the prospect of 'asymmetric warfare' - a menace against which NMD appeared as a plausible first, though hardly the only, line of defence.So much has changed as a result of 11 September 2001 that we need to ask whether events and perceptions redolent of the 'new strategic millennialism' can possibly be of any relevance today. In a word, has NMD become yesterday's issue? Before 11 September, such a question would have provoked indignation on the part of any number of analysts and policy-makers, in Canada as elsewhere, whether they opposed or supported NMD: the question would have been taken, at best, as testimony of the flippancy of its poser and at worst as a signal of malice.At the risk of being thought flippant, or even worse, I am going to suggest in this brief article that NMD has become yesterday's issue. Indeed, as a simple descriptive, NMD no longer makes any sense, and we should rather be thinking and talking in terms of another arrangement, known more generically as 'missile defence.' And while missile defence itself will very much continue to be of strategic significance, for Canadian consumption it is going to be subsumed into the broader and more important concept of 'homeland security.' The latter, in turn, will have important bearing both on the future of 'bilateralism' within the North American security community and on that of 'multilateralism' itself.I develop the argument in a comparative manner by offering a contextual, historical, parallel drawn from another era of strategic millennialism; by encasing missile defence within the context of recent Canadian defence strategy; and by asking what missile defence has to do with the inquiry into the future of bilateralism and multilateralism as these terms apply to American foreign policy.A HISTORICAL PARALLEL FROM THE SAGA OF ARMS CONTROL?For Canadians with a sense of history, the story I tell in this section will have a familiar ring.(1) At the dawn of a new century, their American neighbour proposed to pursue, unilaterally if need be, a strategic initiative portending a fundamental alteration in the balance of power in America's favour. …