Russia's annexation of Crimea is causing NATO to reaffirm its collective defense guarantee, work more closely with Ukraine, and suspend cooperation with Russia.
In a speech to the German Marshall Fund of the United States' annual Brussels Forum conference on 21 March, NATO Secretary General Anders Fogh Rasmussen said "Russia’s military aggression in Ukraine is the most serious crisis in Europe since the fall of the Berlin Wall" which "follows a pattern of behaviour of military pressure and frozen conflicts in our neighbourhood: Transnistria, South Ossetia, Abkhazia, and now Crimea."
He therefore reaffirmed the alliance's commitment to collective defense, which he described as "not just words, but real assets and real actions: more planes to police the airspace over the Baltics, surveillance flights over Poland and Romania." The United States has increased the number of F-15Cs policing the Baltic States until April from four to 10 and France and the UK have offered four fighters each for the next rotation of four Polish aircraft starting in April. NATO has also been conducting airborne warning and control system (AWACS) missions, including by an RAF E-3D, to monitor Ukraine from Poland and Romania, to which France has offered to add an E-3F flying from its own territory.
Rasmussen also announced increased cooperation with Ukraine: support to the transformation of the Ukrainian armed forces to deter and defend against military threats, increasing their interoperability with NATO forces, and greater Ukrainian participation in NATO exercises.
Finally, Rasmussen stated that "we can no longer do business as usual with Russia." He already outlined what this means in a speech to the Brookings Institution on 19 March: suspension of staff-level civilian and military meetings with Russia and of planning what would have been the first NATO-Russia Council joint operation, a maritime escort mission for the destruction of Syria's chemical weapons. NATO foreign ministers will decide on further measures when they meet in Brussels in April.
As Rasmussen was reaching the end of his Brussels Forum speech talking about the need to back diplomatic soft power with military hard power, the lights went off in the conference room, prompting him to ask for "real power." The lights also went out and the Internet went down in the conference's press room as I was writing this, but I presume it was not because the Russians are cutting energy supplies to Europe.