Oct. 12--This space long has argued that national security defines the federal government's principal obligation. The president performs many roles. None surpasses that of commander-in-chief in importance. Issues relating to defense and foreign policy belong at the top of party platforms. As it opened, the 2008 campaign offered the potential for a compelling debate on America's place in the world. John McCain and Barack Obama ably articulate competing visions. Yet the economic crisis ensured that a sustained exchange would not occur. The first debate, for instance, was supposed to focus on national security. The economy led the agenda and proved of greater interest to viewers. Although foreign policy retains its heft, it seems safe to say the election will not hinge on the candidates' positions on NATO. Potential secretaries of the treasury have vaulted over potential secretaries of defense and potential secretaries of state in the public imagination.

We understand.

Challenges relating to the defense of the homeland and to America's standing abroad will not disappear, however. The economic crisis itself is of global scope; its causes include global factors; its consequences will have implications for U.S. foreign policy. At this moment the only so-called superpower does not boast a super economy. America's era of worldwide economic dominance began to wane some time ago. The crisis closes another chapter of American triumphalism. Well might a country blessed and blessing relearn humility's virtues and joys.

References to generational influences and identities typically strike us as contrived, self-serving, and boring. McCain and Obama come from different generations, and for once the distinction might prove defining. McCain was forged by national and personal struggle. His is a world of ideals but without illusions. He understands power's purposes and its limits. A McCain presidency would assert American interests but, we believe, without the unilateralism that has undermined U.S. policy recently. It is impossible to conceive of a President McCain snapping, "Bring 'em on," during the heartbreaking havoc of war. Obama belongs to a generation at once freshingly cosmopolitan -- at ease with a world beyond geography's confining seas and beyond isolationism, ignorance, withdrawal, and other aspects of the American temptation -- and oblivious to history made by others. Fouad Ajami, professor of Middle Eastern Studies at Johns Hopkins, writes:

"The Obama way is glib: It glides over the world without really taking it in.