As Russia completes its invasion and eventual annexation of Crimea -- and possibly threatens more Ukrainian territory -- one can be forgiven for asking, "Where's NATO?" With NATO Secretary General Anders Fogh Rasmussen in Washington this week, perhaps we'll find out.

NATO's job No. 1, set out in the Washington Treaty, is to defend the territory of its members. Beyond that, it has often served to project security and stability in Europe. It is the organization that faced down the Soviet Union without firing a shot, deterred nuclear Armageddon, and gave inspiration to dissidents and other democratic activists in Europe's East. NATO also stopped the killing in Bosnia and Kosovo, and helped over 100 million Central and East Europeans establish security as new, democratic, market-driven societies.

Since the fall of the Berlin Wall, NATO has engaged successfully in crisis management, building far-reaching partnerships, bringing in 12 new members, shifting toward deployable, sustainable military capabilities, and attempting to build a relationship with Russia (despite Moscow's demonstrated antipathy).

No NATO territory has been invaded by Russia, so NATO's collective defense commitment has not been formally tested. But NATO allies in the East -- the Baltic States and Poland, for example -- are rightly worried about Moscow's intentions. And, perhaps even more importantly, non-allies -- such as Moldova, Georgia, Ukraine, and Azerbaijan -- are watching to see whether NATO pushes back, or accedes to a revived Russian sphere of influence over pieces of the former Soviet Union.

As we approach the 25th anniversary of the fall of the Berlin Wall, Ukraine has been invaded and NATO is almost invisible.

To be fair, NATO has been awash in activity. The North Atlantic Council (NAC) met in special session to discuss the crisis, and has issued three statements -- one where it treated Russia and Ukraine equally, calling upon "both parties to immediately seek a peaceful resolution through bilateral dialogue"; and another where it promised to "pursue and intensify [its] rigorous and on-going assessment" of the situation. In its third statement the NAC urged "the Russian Federation to de-escalate the situation." 

NATO held meetings of the NATO-Russia Council (March 5) and the NATO-Ukraine Commission (March 2), and hosted a visit by Ukrainian interim Prime Minister Arseniy Yatsenyuk (March 6) at the alliance headquarters. The Euro-Atlantic Partnership Council, comprising NATO and all Euro-Atlantic partners (including Russia and Ukraine) discussed the situation on March 14. Secretary General Rasmussen has made several press statements. NATO has cut back on cooperative exchanges with Russia, offered to increase partnership activities with Ukraine, and sent AWACs surveillance aircraft to southeast Europe to better observe the Russian offensive. On a national basis, the United States has increased its participation in Baltic air-policing, added to its air defense contingent in Poland, and sent a ship to conduct naval maneuvers with Romania and Bulgaria in the Black Sea.

Yet all that activity is just that -- activity. Missing is strategic purpose, coordinated action (not words) and real effect. Nowhere has there been a credible threat of action, which might deter Russia. As Russia gobbles up territory and conducts major exercises on the borders of the Baltic States and Ukraine, the United States talks about off-ramps, Washington and Brussels lumber toward phased, underwhelming sanctions, and NATO cuts back on cooperative activities. NATO seems to be stuck operating in the logic of partnership, rather than the logic of defense and deterrence.

Especially as Russia threatens to move into Eastern Ukraine -- and perhaps now also to annex Transnistria, from Moldova -- NATO needs to re-learn the logic of deterrence: the willingness to use force if necessary, and to decisive effect, in order to deter conflict. While Crimea may be lost already, deterrence is all the more relevant to prevent further Russian incursions into Ukraine and other areas of Eastern Europe.

Yet today, while NATO talks about de-escalation, Putin thinks in terms of escalation dominance -- something at which NATO used to excel, but refuses to consider today. If Putin persists, there is no one to stop him.

Clearly, the U.S. and EU strategy is to put in place travel, economic, and financial sanctions targeted against key people in the Russian leadership, oligarchs, and state-run businesses, rather than consider military steps. But Putin clearly believes he can weather these sanctions, up the ante, and outlast Europe and America's willingness to pursue them. Indeed, the list announced on March 17 -- intended to be a shot across the bow -- instead came across in Moscow as weakness. 

By Putin's logic, the acquisition of territory is permanent and strategic; sanctions are temporary. Add to that his belief that Russia's potential countersanctions against Europe -- especially in energy -- will force the West to back down. Indeed, it's almost a game to him, with Putin now reportedly deciding which U.S. leaders he wants to sanction. Putin is not only undeterred, but eager to ride out whatever U.S. and EU sanctions are put in place.

Not so many years ago, members of NATO saw it as a critical goal to produce a joint policy, with coordinated action and statements, in order to concentrate effort and achieve strategic effect. Today, it appears that several allies aim instead to prevent NATO from making a strong statement or -- worse yet -- taking action, so as to avoid "escalating" the crisis.

NATO cannot function without U.S. leadership -- and with the United States studiously avoiding any suggestions of military response to Putin's military aggression, NATO is almost by definition on the sidelines.

Yet even if the United States were to suggest a far more robust NATO posture now, it would be an uphill climb. Berlin also wants to avoid a serious NATO policy backed up by action, and the de facto situation in Crimea and along Ukraine's eastern border is daunting for all Europeans. Ever since the former German chancellor -- now Gazprom employee -- Gerhard Schroeder was in power, Berlin has sought to minimize NATO's military engagement, political role, and any push-back on Russia. Angela Merkel has moved Germany toward a slightly tougher position, but only slightly.

Even with Allied hesitation, it would be far better for the United States to put the most significant security issue in Europe in 25 years squarely on the NATO agenda, rather than to acquiesce and keep NATO out of the picture. NATO is, after all, the essential venue for consultation among allies under the Washington Treaty.

In the wake of Russia's imminent annexation of Crimea, here are a few specific suggestions of what NATO -- with strong U.S. leadership and participation -- should and can do:

•Shift the logic of NATO action, from partnership to defense and deterrence.
•Issue an iron-clad statement articulating the absolute commitment of the alliance to defend the territory of all NATO member states, no exceptions.
•To back up this commitment to collective defense, update and put in place defense and exercise plans for each and every allied member, and strengthen air defense assets deployed to the Baltic states.
•Send NATO military forces (ground forces, not just AWACS planes) to NATO allied territory bordering Ukraine to conduct military exercises.
•Determine that any further assaults on Ukraine's territorial integrity beyond Crimea represent a direct threat to NATO security and, accordingly, issue a statement saying that any such efforts to break off more territory will be met with a NATO response.
•Task the NATO military authorities to draw up contingency plans in the event of a Russian military invasion or subversion of eastern Ukraine.
•In concert with the European Union, NATO should sell new military equipment to the Ukrainian armed forces, based on U.S. and EU loan guarantees.
•Also in concert with the European Union, agree to an embargo on arms sales to Russia, including French "Mistral" ships and German live-fire training gear.
•At Prime Minister Yatsenyuk's request, provide NATO-country advisors and trainers to assist the Ukrainian forces in defending their country.
•Expand intelligence sharing with the Ukrainian government, and allow Ukraine to post a military liaison at NATO's Supreme Allied Headquarters in Belgium, to facilitate real-time intelligence sharing with the Ukrainian armed forces.
•Counter increasingly rabid Russian propaganda pitched at ethnic Russians in Eastern Europe with increased funding for broadcasting outlets such as Voice of America, Radio Free Europe, and local efforts -- such as Latvia's center of excellence in strategic communications.

None of these actions place U.S. or NATO ground troops in Ukraine. But together these actions, they may be sufficient to get Putin's attention. And if NATO shows unity of purpose and stands its ground, it can deter Putin from further land grabs and only then see a possible "de-escalation" of the crisis. None of this will happen with out determined, courageous U.S. leadership -- which is what makes NATO Secretary General Rasmussen's meetings in Washington this week so important.