Under the grey, wintry skies of Paris. the foreign and defense ministers of the world's greatest politico-military alliance gather this week. At NATO's annual meeting, the agenda, as always, is simple: the defense of Europe. But this year there is a mood that old assumptions are outdated, old battle doctrines need revision, old relationships have shifted.
The urgency of fear that forged NATO's first army has long vanished; so has the invulnerability of the U.S. nuclear deterrent that so long buttressed NATO's troops from afar.
Within Europe itself, NATO's policymakers confront...